Thanks for the tip, Steve and Anna. This morning we walked down to Mullock and found two in the large trees at the bottom of the Marloes road, next to your house. They were "singing" enthusiastically (squeak, sqawk, sqeak, squirk) and were very visible in half-leaved ash trees.
We do sometimes get them passing through our garden, and in the mid-2000s they nested two years running, once in an open-fronted nestbox which we put up specially for them. The first year we put the box amonst creepers and quite sheltered - it was ignored in favour of a very exposed cranny in some brickwork. So the next year we moved the box to a very open postion, no trees or shrubs around and facing south west - they loved it and raised a brood there! But we've hardly seen any here since that time.
