Hi Nick,
You're in the same position that many of us have been before, the only difference is that some of us have driven the cars beforehand and hence we know what we'll get out of the restoration. For someone like yourself I can see why you're asking the "is it worth it ?" question.
As John has said, it is very unusual for your average guy to restore a car and make a profit, most of us spend way more than the car is worth. Buying labour is the big killer, parts and materials are a relatively small part of the bill. To be perfectly honest, if you look at buying parts for modern cars then ours come out pretty cheap !
£7k for a respray on a fibreglass car I would say is in the mid range, I know of £8k resprays on Elans and they are much smaller/easier to do. I would have said Alex's £10k was more like the going rate for a top notch paint job so you're not doing too badly on quotes. You could perhaps shave a bit by presenting a bare shell on a trailer ready for preparation and do all the assembly yourself afterwards maybe ?
Otherwise the budget is just what you're comfortable with and we've all got different priorities. If you want some man-maths to make you smile, try this for size....
If it costs you £15k to get a nice shiny Europa on your drive then you could spend that same £15k and buy yourself an Elise, a newish sporty Ford, a 4-5yr old Audi TT, all of which would cost you more to run with insurance and road tax. If it's a new car then in order to sell it later you'll need some main dealer servicing thrown in as well.
Of course they won't steam up or leak in heavy rain, you won't feel that every trip to the supermarket is a Grand Prix and you'll miss the tensions of wondering if you will actually get there and back without some roadside maintenance, but you can't have everything with new cars.
But in 2 years time they'd be worth roughly £4k less or maybe £5-6k if the car was newish and you've probably spent around £2k running them. Whilst your Europa might not have increased a great deal in value but at least it's cost you buttons to run, hasn't lost any money and you'll be really good at fixing things..... there's always a silver lining
