EMU 5945 1970s Datchet -ROneg-009
The name on the building is Moderector - which I believe is an Irish company making pre-fasbricated buildings.
I think this is Datchet, looking in the up direction, taken from the station footbridge. Downgraded HAPs were allocated to Wimbledon depot and used on Waterloo - Weybridge/Windsor services, Windsor and Eton Riverside being the next station along, a little to the west, behind the photographer.