thanks for your quick response but after i posted here i thought i would e mail the publisher with this...

'hello,sorry to bother you but i wondered if you could help me.i recently found a hardback copy of this book(i remember buying it 2nd hand in the 80's),and i wondered how i would go about finding out if it is a first edition

it has the isbn no 0-86140-089-5,the book itself is green with gold title on spine with 205 pages(and a few blanks at the end)
the protected cover has a stickerwith a review of strata covering up what was written on the cover and says at the back

colin smythe ltd
gerrards cross buckinghamshire
printed in the usa

thanks for your time'

and i got the reply the same day on a sunday,what a gent

'The sticker may have the word Strata in the first line, but the Publisher's Weekly review is of The Colour of Magic, if it is what I think it is. Certainly from everything you say, it is a copy of our first edition, worth some thousands - but depends on condition, of course.'

i felt a bit daft as i didnt read the sticker properly and it is a review of the colour of magic

anyway must be my lucky day