The Charge Of The Light Brigade Plus 63 Years:The Lighthorsemen

from the description where I found this in youtube:
One for the surplus fans. In 1917 the British and ANZAC forces in what is now Israel were running out of water. While the British and New Zealanders had tried to take the town for months, a last ditch attempt was devised using the Australian Light Horse.

Expecting the Australians to advance within a mile, dismount and attack on foot, as they normally did, the Australians mounted the last successful Cavalry charge in the history of modern warfare - In three hours they achieved what the British Army had been attempting for three months.

Ironically, all Australians know about Gallipoli, possibly one of the greatest disasters of WWI, but nobody knows of the amazing achievements by the Light Horse in the dark days of 1917.
from wikipedia:
The Lighthorsemen is a 1987 Australian feature film about the men of a World War I light horse unit involved in the Battle of Beersheeba.
Palestine, 1917: The British advance in the Middle East has been stopped by the Turkish line running from Gaza to Beersheba. The British high command orders an attack on Gaza. Men of the 4th Australian Light Horse Brigade are in the thick of the battle. However, it is a failure. Four Australians, Frank (Gary Sweet), Scotty (Jon Blake), Chiller (Tom McKenzie) and Tas (John Walton) are a part of the 4th Light Horse Brigade. The four men are battle hardened and have been through Gallipoli and most of the war in the Middle East up to that point. Meanwhile, a young railway worker from country Victoria, Dave (Peter Phelps) decides to join the Light Horse against his parents wishes. Dave is determined to join up and serve his country and is excited about the prospect of fighting. Back in Palestine, Frank is wounded by a capture of a Turkish sympathizer and is taken to Hospital. The blokes in his troop find life without Frank boring and visit him every time they can. However, not long after, the men receive news that Frank has died of his wounds. The men are distraught and learn that they are receiving a new replacement for their troops, which turns out to be Dave. After basic training, Dave is transported to Palestine where he meets his new troop mates. At first, Tas especially regards Dave as another young kid trying to get himself killed, however the rest of the blokes are happy to have Dave along.

Not long after, Dave and the rest of the squadron are dispatched to attack a Turkish recon patrol near their camp. The Australians ambush them and the Turkish decide to retreat, the Australians gun them down however Dave does not, he is terrified. After the fight, Dave and Tas are ordered to look for Turkish survivors. A Turkish survivor targets Dave and pins him to the ground before Tas kills the Turk and saves Dave. There are doubts among the ranks if Dave will prove to be a good soldier. A day or so later, the Light Horse camp is bombed by a German Bi-plane and in which Dave is wounded in the hand. He is taken to a field hospital where he meets an Australian nurse named Anne. The two begin flirting and before long bein a relationship, Dave is reluctant to return to his unit but assures Anne he will come back alive. After arriving back, he is greeted warmly by the men except Tas who still feels Dave is not a soldier.

During another attack on a Turkish position, Dave once again cannot bring himself to kill the enemy and it nearly puts the entire troop in danger. Tas reports his actions to his superiors who also sees Dave's inability to fight. His commander offers Dave a transfer to the Medical Corps, where he will be unable to carry a weapon and will be out of the fighting. Dave accepts the transfer and fits in well with his new unit. Tas and the others are glad about the decision and agree that giving him a transfer was saving his life.

At the same time, the British are planning a new offensive with the capture of Beersheba. Major Richard Meinertzhagen (Anthony Andrews), escorted by Tas, heads towards the Turkish lines under the cover of a birdwatching trip. When attacked by Turkish Cavalry he leaves behind false documents indicating that the attack on Beersheba will be a diversion.

The Australians are dispatched to fight in the offensive and leave for Beersheba immediately. The Australians are sent in with limited water and supplies to last them the journey. The Australian's bombard the town and the Turkish realize that the town is about to be attacked and prepare for a siege. However, the German military advisors believe it is a diversionary attack and refuse to send reinforcements. The British cavalry attack on the town was unsuccessful and another attack by New Zealand forces also failed due to the heavy artillery bombardment by the Turkish guns.

The British command realises any attack upon the defences will fail. However, the Lieutenant Colonel Murray Bourchier (Tony Bonner, with the support of General Sir Henry Chauvel (Bill Kerr), ask the British to use the Australian Light Horse. The rationale is that the Turks always wait until the Light Horse dismount before opening fire. The British give the go ahead, however they think it will be a suicide mission. The 4th and 12th Regiments are ordered to be the attacking force. Dave and the rest of the Medical detachment brace themselves for casualties and are ordered to go in behind the Light Horse.

The Turks report Australian Light Horse lining up to charge, however General von Kressenstein (Ralph Cotterill) is adamant the Light Horse will not charge and orders the Turks not to open fire until they dismount. The Australians begin advancing on the Turkish positions, gradually speeding up until Major Bourchier orders them to charge. The Turks realise too late that the Australian Light Horse are charging the fort and open fire. Artillery fire is sporadic and inaccurate and the Light Horse covers the four miles to the Turkish trenches quickly. The attack is so fast the Turkish infantry forget to adjust the sights on their rifles as the Light Horse get closer, eventually firing straight over the Australians' heads.

During the charge, Tas and his horse are hit by an artillery shell and he collapses. The rest of the men are unaware of this and continue on. The Australians make it "under the guns" and jump the Turkish trenches before dismounting behind the lines. Dave comes along to check casualties and finds the dead body of Tas lying in the sand. Filled with rage over the death of a mate, Dave grabs a rifle and hops on a horse and gallops in to help against the orders of his superiors.

The Australians manage to capture the first Turkish defences with hand to hand fighting. Scotty and a few others manage to take control of the guns. Chiller however is in the trench fight and begins bayoneting the Turks. Chiller is shot by a stray bullet and falls to the ground wounded. Dave has now reached the fight and notices the wounded Chiller on the ground in pain. Chiller is glad to see Dave and begins to patch him up. However, a Turk throws a grenade nearby and in order to save his mate, Dave dives on the grenade, which blows his back open. Chiller hollers for a stretcher bearer and both Chiller and Dave are taken away by Medics.

Scotty however continues to fight on in the town. He and a few others manage to gun down the remaining defenders before most of them surrender. Suddenly a few wells burst and he is suspicious and follows a cable to a small house, where he finds a German Officer trying to blow the wells. Scotty captures the officer just in time. The attack was a success and the Australians miraculously suffer only 31 dead and 36 wounded.

The story ends with Dave and Chiller miraculously surviving their wounds and meeting up with Anne at the Hospital. Scotty is promoted from Corporal to Sergeant and is the leader of the troop.

The Coda states that Anne and Dave were married after the war and lived long and happy lives producing many children. Chiller returned to his unit and served out the rest of the war and became a farmer after the war. Scotty survives the war but is later badly wounded and marries after the war and lives a long and happy life.