Maybe could also be 1028 as had the same grille and was also still running at this time.... and whilst I was in the archives I came across this phot of an unidentified Western at Tilehurst in early July 1976 on a westbound service.
I think it may be 1056 Western Sultan, judging from the ventilation panel below the driver's window. Can any Western expert out there confirm.
I'll ask my mate who updated my records he may know can't work out from my mine!

52 years for me this late summer.