The British Airways ones certainly were brakeless from the LHS
Bristow, having not been successful gatting the registration GTIGA off it's Tiger Moth owner, then went the whole hog and used up the rest of the alphabet apart from GTIGQ which was verboten. They started running out of contracts with GTIGW so there was a problem with the other three.
They arrived at Redhill in a green state and they were sold/leased on to Canadian Helicopters where they received Canadian registrations. Fortunes changed and they came back to to UK and went onto the North Sea in British Airways Helicopters/BIH livery but with a Bristow GTIG* registration.
I have a feeling that Bristow tried to buy them back but helicopters were like hen's teeth then.