Bitsa, i got round that problem by drilling the pan for extra fittings. Florence did state that he wouldn't mind finding a aftermarket seat for about £35. That is the price of a cover 
I have a orignal 550F seat (without rails) for 40.
is it the same dimensions as 500/4 seat? Sorry, scrub that I've just looked at a picture and it's a bit of a different shape. Thanks all the same.
I think I will get a cover and try that. Thanks to all for suggestions. I looked at Tony Archer, most excellent but too expensive.
All the best, Steve
