Thanks aowen. You're proving to me something I should have known anyway - most of what you think you know when you're young and foolish is actually wrong, and so you remember it wrong!
I do remember the Jubilee Coaches destination blinds though. Whether they were made in house or what I don't know, but they were full of spelling mistakes - "Harpendon" led to a furious letter to the Herts Advertiser from an older chap of that town - and that really didn't improve their image.
There must genuinely have been at least one GMPTE vehicle in the Sampson's fleet, because it still carried an advert for a pub in Bolton. Welwyn Hatfield Line started up with a fleet of new Optare CityPacers, but they added some older vehicles too; there was one which was all over red and which the drivers dubbed The Fire Engine.
In the early days of Uno - then called Universitybus, and the services were initially not available to the general public - they had a couple of vehicles in the Scottish shape, which were never a common sight in the south of England.
I'm reasonably sure that the G4 was eventually the only G route standing. Herts CC chose not to retender most of them once WHL had come onto the scene, but the G4 carried on. It was registered as commercial once Sovereign had taken Sampson's over, and then withdrawn within a few months.
In the days of the one driver on the G4, he was a smoker and allowed his passengers to smoke, which by then was becoming unusual. WHL never allowed smoking (although some of the drivers did it anyway ...), and so my parents wanted me only to use their services.
I lived in Panshanger in those days - my move to Kent was in the late 90s - and for a while we had eight buses per hour from WGC. The G4 ran every 20 minutes, the WH Line rival the WH4 every half hour, and there was also the WH7 (WH Line WGC - Panshanger - Hatfield), the 366, and the 724.
The 366 no longer goes that way and the 724 now skirts the edge of Panshanger past the golf course and doesn't serve the shopping centre, so the half hourly 401 is what there is. Clearly worse than 25 years ago!