Wish I grew up in a MK2 Oh yeah I did 
Ah the memories of burning oil smell!
The missus has a Britax Prince in the back of her 3 door MK2.
I've got a Britax Evolva 1-2-3, which was one of the few that would fit the Corrado (the rear belts come out of the rear doorcards) - but it also fits the Golf fine. I find the Evolva a lot easier to install and use than the Prince, but it cost £100. Still, it covers stages 1, 2 and 3, so you could make it last a while.