A bit of useless information, it was the choice of the Officers as to what revolver they wished to use as long as it accepted issue ammunition at the time.
However, during the filming:

Lt John CHARD VC used a Webley VI revolver and his real one is now in the Royal Engineers Museum at Brompton, UK.

Lt Gonville BROMHEAD VC used a Dean & Adams .455 revolver. He was a Lincolnshire lad whose villagers at Thurlby on his return to UK after the battel clubbed together and bought him a Stanton .45 which was not clearly used at Rorke's Drift.

The bolt action rifle used in the film in the centre and rear ranks ( which they hoped would be out of camera shot) were in fact Lee Enfield MK1 CLLE .303 and Martini- Enfields bolt action rifles.

Historically this period of the Britishicon Army anyway was a diabolical time as ammunition sizes varied greatly even in the same units, from revolvers to rifles. The first breech loader purchased for the British Army was made by William Tranter in 1863, a .44 calibre revolver using rim fire cartridge . The only rim fire weapons to be issued by the British Army and it was Tranters revolver which was taken into service in very limited numbers.

William Tranter interestingly enough went on to become the founder of the Birmingham Small Arms Company.
Thats why when I did my research into Parker Hale and its history, I was moved to see that we, as a nation, lost so many great weapons manufacturers in one City of our country.