Longdog,
I see that you are from Kent mate which is a bit far from North Yorkshire, but i know a gun smith there selling a mint condition Weihrauch HW80 with silencer and good scope for £200 which is a real steal buddy.
Here is the info
Mr Kev Burrill
Tel: 01677 424447| The Old Blacksmiths, The Wynd, Bedale, North Yorkshire DL8 1EW
A HW80 is a real good rifle and will do what you want buddy.
Just remember that when shooting in barns you have a good backstop behind the bird before taking a shot or you will be missing some roof tiles for sure.
Si