We live on the edge of a small town surrounded by countryside, in a modernish house (approx. 20 yrs old) & was amazed at how many bats are flying around + we have them under the roof tiles.
Sometimes I can hear em when I'm in bed, climbing/scuttling around. I love the little flitter mouse

On the ground outside, under where they go in to roost, there's loads of droppings/guano, which is swept up & used for the flowers.
4 or 5 years ago I got in touch with Natural England for advice, because we wanted to renew the roof line (barge boards, soffits, guttering etc) I was a little worried that because of their legal protection that there would be some prohibited cost, but wanted to do it right.
It was in June & a few nights before they were due to come out to see me, I stood outside for nearly 2 hours & counted out from between the soffit & stone wall ................258 bats.
When I told him how many there were, he said it was a decent number, BUT probably only half of what would actually be there. These were the mothers & the young would still be inside.
Modern housing is preferable apparently as a nursery because of their preferred temperatures & also access & security.
A really interesting guy to speak to & he gave us advice on what to do & what to inform any workmen to do. They sent out an official letter within a few days to confirm everything.
We just had to wait until after Sept for any work to be done & the criteria was something really simple. A gap of a few m/m for a length of around 250mm. Simples.
Actually this year, we've had next to none in, but they can change/return to different locations, so hopefully they'll be back in numbers next May.