I went for the RainSport 3 tyres in the end, 205-50-15.
They feel OK; I've only driven it back from the wheel refurbisher's so no real testing; already noticed they are more comfortable than the Toyo proxies 205-45-16.
Here are the refurbished wheels

and on the car


For those interested here are the details:
Tyres; Uniroyal RainSport3 205-50-15, £51.89 each (free delivery) from Tyreleader.co.uk; they are currently £50.19.
BBS Centre Caps Carbon with Silver Logo BBS 56mm, £47.49 for 4 (inc delivery) from PWM Motorsport.
Wheel refurbishment including fitting the tyres and balance, £230.00, rimtecrefurbs.co.uk based in Meopham Kent.
BBS wheels, 2nd hand from eBay £45 for all four, yes they were less than the price of the new centre caps!
Thanks for all your help,
Steve.