Thanks for everyone's help - save that of "weatherlawyer" who I can only assume uses newsgroups because nobody in the real world can put up with his lack of manners. Everyone else has been extremely helpful.
The paint was Leyland high gloss red base with a few colours added in the shop to give Post Office Red. Since that is a well known brand I suspect it was my lack of stirring properly combined with too much paint- oh well, lesson learnt for next time!
Ben