Have thought of that BTK, but I very rarely see BTs around my garden at any time of the year, so I'm rather loath to go that far and end up with nothing.
I had the opposite problem in Dublin, Ireland.
All BT's never seen a GT ever for some reason. No Long tails either there. Had a very healthy House sparrow population, so I would have tried a nestbox like Paul's or a terrace nest setup.
