Pilot Attack Sight Mk2R Display Unit Info Required

Looking for information pertaining to a PAS Mk2R Display Unit, Sect Ref 8B/5048 or possibly 8B 1270-99-4506257, which sits on a Test Set Type 2 Sect Ref 8B/4002.
Have tried net searches to no avail. Any info from the 1086 or relevant APs would be welcome. No picture yet.