In reply to Confused Chimp:
Adventure Peaks in Ambleside has often got stuff other shops dont stock outside the two or three main boots most sell so it worth a look.
Lakes climber/runner and Climbing shop both also in Ambleside have good ranges and are worth a look. These three shops alone will probably have most boots you will find.
Needle sports in Keswick is definately worth a look especially if your after other climbing bits, but otherwise probably won't sell anything that isn't in Ambleside. If you do visit Keswick George Fisher is worth a look for thoroughness and Cotswolds (there is also one in Ambleside in the Garden Centre newly opened if you want to visit them).
Happy shopping.
Craig.