Rich, just use the "search" function at the top of this page. Type in "Williams & Powell" and you'll get a lot of responses. You'll find it there. Can't understand why IE isn't doing it for you if you've entered the entire address. Works for me.
Have no opinion of the value of the gun you're looking at. However, unlike American guns, the maker of English guns has little influence on its value unless the gun is from one of the top makers--London best, for instance. If you have photos, it would help us if you'd post them here. Overall, generic British boxlocks seem to be suffering from the economy and prices have been slumping, IMO.