Note how Thorn used a metal clip to mount the cap spring on, and not just stuck through a plastic hole like Tamlites.

I'd love to say it was done on purpose for strength but it was only due to some models having an earthing strip contact in the batten, so the metal spring provided a convenient earthing point. The later T8 PP no longer had this so was mounted using the plastic clip and hook method

That did brake on the 80s version but is a lot better clip than tamlites, the amount of times I have seen the lamp holders stuck on with brown tape lol

Yes, still better than the Tamlite - think it was made of polycarbonate on the PP?

gets a 5* from me