Bats are a protected species across the UK and Europe, so if you’re planning to do any work that might disturb them, their breeding sites or resting places, you need to be sure how many bats there are and of what species before doing anything.
If you’re planning any work, you will need to commission a bat survey – as whether it’s stated outright in your planning consent or not, it’s a legal requirement to make sure your project won’t affect any bats.
It’s the duty of every planning authority to consider whether it’s likely that your proposals will have an impact on bats, and they need detailed and robust evidence about how bats use your site, and what measures you will be taking to mitigate any impact on them.