It still has its cabside number but the smokebox plate is missing. This neg came as 6374 but this had outside steam pipes when withdrawn in 1962, so clearly it is not this loco (thanks to RIck Brewer for the info). Looking at the original neg the number definitely has 7 in it and assuming the date is correct 6378 was the only loco still in service and was allocated to Didcot so I think it is safe to assume it is this loco.

Furthermore there is a photo of 6378 in the same sequence of GWR Moguls that was taken at Oxford in May 1964. It show the same lime scale marking bands on the boiler together with the missing front number plate and looks like an exact match! Looks like the date is correct.