I wanted a .177 Merc S about 18 months ago, and after putting out a call on the BBS, was directed to one for sale in Penzance in Cornwall (about a 9-10 hour round trip from Southampton)
(Actually better than it sounds as I stopped overnight at the parents who lived in North Cornwall at the time)
Cost me £200 but its at least a 9/10.
Every time I use her she brings a smile to my face.
Just one word of warning - if you decide to sell her - think carefully before you let her go - there are plenty of examples of those who have regretted letting guns go after having second thoughts later ...
Ultimately, the question is what is the gun worth to you, not to everyone else