I have a photo from the prospect stile area (i.e. about 700 m North of Kelston Round Hill) that clearly (well on the original it's a speck, but a clear speck) shows the old Severn Bridge and vaguely shows the Welsh hills in the background. It's from the same 'photo shoot' as this one
http://www.themodernantiquarian.com/image.php?image_id=12470 - but a slightly different angle.