This evening I fired up the bat detector after seeing three bats via infrared cctv doing circuits around my back yard. Impossible to say their size accurately from cctv, but their loudest (fast ticking) chirps were heard at 50.1 khz, which is pretty well smack on the Bechsteins reported frequency. This is definitely not the clapping chirps i'm used to. I was quite surprised as I had automatically tuned to 45khz expecting pipistrelles which are very common where I am located near Narberth. I would be pretty excited if a new species has moved into my area. I have been mulling over building a rocket bat box for a couple of weeks. I think my Easter weekend to do list just got longer :-O