I've found it very helpful in researching this subject to make use of the web site produced by Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust (BBOWT) which can be seen via this link.
I am trying to get a clearer picture of what local government is legally required to do in this respect. I'll post a summary of my notes in due course but here is a link to the BBOWT page where you will find two documents which give guidance notes.
Click on the BBOWT link to go to their home page.
Click on the Advice heading.
Select Planning Issues.
Scroll down to Planning and Development Sector.
Select the relevant doc.