I used to work in this area, and it was amazing how many people in the UK wake to find a bat flying around their bedroom and try to shoo it out and get bitten, or wake when they are bitten at night whilst sleeping!
Where did you work, the Bat Bite Reporting Hotline? I don't know anyone who's been bitten by a bat, and I know loads of people who live rurally with every window and door permanently open. I do know someone who was bitten by a badger, but it didn't get in through a window.
Even I've never been bitten by a bat, and absolutely everything bites me. Ticks, leeches, insects (not just the usual suspects, I've been bitten by ladybirds), fish, amphibians, reptiles, birds and mammals of all shapes and sizes have had a go. A tiny lizard once clamped its jaws onto the end of my little toe and sat there for about 10 minutes trying to work out how to swallow the rest of me. The largest thing that's bitten me with intent - drawing considerable amounts of blood - was a Shire horse, but I've also had an elephant stuff my hand in its mouth (that more of a suck than a bite). I have been playfully chewed by lions and violently snapped at by toads, but I have never been been so much as nibbled by a bat.