Natural England guidance on chemicals not affecting bats is hard to find on gov.uk. We have uploaded a copy of “Natural England Technical Information Note TIN092 Bat roosts and timber treatment products” [TIN092_Bat_Friendly_Timber_Treatment], which is the First edition dated 15 March 2011. This gives a list of those commonly available products currently approved as remedial timber treatment chemicals and products in bat roosts. This was an update to the information in the 3rd edition of the Bat Workers Manual.
We know the list is not comprehensive. If you can’t find what you are looking for, you may be best to get us to ring Natural England on your behalf. They are very friendly and generally able to make a quick response on the subject.