Bats are a protected species in the UK. This means that it is a criminal offence to intentionally or recklessly kill or capture, disturb a place of shelter or destroy the resting place of a bat. A roosting site can be protected even if there are no bats present. Furthermore, a bat survey needs to be undertaken BEFORE a planning application can be determined.
The other compounding fact here is that the survey can only be completed at suitable times of the year, normally May to September.
In our case, we are not likely to be submitting a planning application until after September, so if it turns out that we need a bat survey then we will have to put everything on hold until the following May when the survey can be completed. Not a great result.
Talking to the existing owners, it would appear that there are bats in the area, so we have decided to get a bat survey completed now just in case. But it is another added expense. Around £1,000.