GKN fleet
 

GKN operated a fleet of HS125, King Air, Islander and Bolkow 105. For ATC, did they use registrations, or did they have a company callsign and flight numbers?

I can never recall them using company callsigns back in the 70s and 80s, it wasn't that common for non-airline operators using them. Surely they would have needed and ICAO code to have done.

By the way, love your location - I take it "The Buccaneer" is the old residents bar at the Excelsior??

Yes, always a good pint of M&B Mild there.