I get the point your making about services pre-deregulation, but the others (whether they came about post 86 or not) all had a local identity too, whether they were as historic or not.
Low Fell Coaches were running into the 90's on their Cross Tyne Service and for a period, yes it was unique - perfect branding for the 24, which follows a similar route to theirs.
There are certainly arguments that Redby (brand the 99), Calvary Coaches (alternative to Washington Street Shuttle) and Gypsy Queen (13/14), Northumbrian Coaches (instead of Bargain Bus) are synonomous with their home areas too. Any more or less than the Venture, Diamond or OK companies?
I have always wondered why GNE (or Go-ahead) went about buying the local companies they did, even as recently as Stanley Coaches. It certainly didn't give them access to a whole fleet of new vehicles (existing ones were usually disposed of), it didn't give them new routes (routes were usually ended and if GNE wanted to, they could have ran a rival service) - the only reason I can come up with, is that by buying smaller 'competition', it opened up a monopoly in a certain area. Certainly the opposite of what de-regulation was supposed to bring about.
RE: Go North East