I feel your pain. I now have some schweger temporary bat boxes if you need them. You may be lucky and get away with a bat box built into the gable end, this is not too intrusive but if they identify brown long eared bats you may need to provide a bat loft. I built our 2 houses at the edge of a 502 house new development and these are the only 2 houses with any bat mitigation provisions. I ended up paying over £9k to the ecologists but the hammer was the delays that led us into the 10% inflation era. That really hit the pocket.