RCS, Thats a nice example marked to the The Dorsetshire Regiment, the R before the weapon number I think is Reserve and would indicate the 3rd battalion.
dylpickle, Like BR says it looks like a Japanese Arisakaquillion but the muzzle ring is correct hight etc for a 1907, apart from the square edges it looks the same size as a 1907, just the blade that looks out of place regarding the ricasso and fuller, a point like that would normally indicate a DP bayonet on a standard 1907. maybe a film prop knock up ? or a bad repro ?