A Game of Thrones, UK 1st?

Hi,

I brought A Game of Thrones about 3 or 4 years ago from Amazon. I think I paid 0.50p for it at the time. I wonder if it is not a UK first edition. The book is red and shows some fantasy drawings on the front (with curtains all around). How can I figure out if it is valuable?

Thanks a lot for your help,

Marion