I would say a big old Saab a turbo They are being given away at the moment and as far as reliability goes you cant go wrong You might even like a convertible
What do want from your weekend car? As that will help you decide the budget, for example someone can spend 100k on a weekend toy, so you need to give an idea.
Spend £10,000 on a Japanese import. You’ll find what you need, be it a drift mobile (chaser), a rally mobile (Impreza of any sort), a track car (Cappuccino, Type R or any sort) or a toy (MX5, S2000).