Many thanks for that reply. That has certainly helped me a lot and also reassured my own thoughts and understanding.
So to clarify with Query 1, on FD30 doors, installing hardwood lipping should be acceptable and deemed an improvement to a door not ideally suitable due to the large gap and I can be fairly confident is certifying these alterations?
We are being approached more and more regarding upgrading "Fire Doors". I state Fire Doors in this way because I cannot guarantee or evidence these are, neither can the client. these doors are installed in residential blocks of flats