Thanks for that Nicos - we have an oak tree at the bottom of the garden (see red circled area on following images), and as you can see there's plenty of plants/bushes/trees and alike right next to the house.
House - looking North:
http://i93.photobucket.com/albums/l7...ouse-North.gif
House - looking West:
http://i93.photobucket.com/albums/l7...House-West.gif
The Oak is covered in Ivy, which the squirrels love.
Looks like I'll need to get me some meal worms.