Amoco - Park Road Garage, Langley, Iver, Slough, Berkshire SL0 0JG 1983

Despite the clue of the phone number indicating Slough area I haven't been able to get any further than that.

 

Edit Update:- Thanks to Dan's comment below this now identified - now a Kwik-Fit.

www.google.com/maps/@51.5189338,-0.5250652,3a,75y,218.92h...

Done