Hi Martyn, photos of bats in flight do appear in books on the subject, (obtained by sensors I always thought). There shouldn't be any problems using flash photography on bats that wouldn't also apply to other mammals. Good luck with that.
Slightly off topic I know (but no more so than 'Jupiter and its Moons'), does anyone have any advice or tips on photographing bats? I have a couple that fly quite low over my garden most spring and summer evenings around twilight so I thought I'd have a go at getting a photo with flash. Would using flash harm the bat in any way and would it be acceptable to try? - I'd probably miss every time anyway! Any thoughts and info gratefully accepted.