@007 RED - thanks for the detailed reply, it really helps ????
That is the same material that I’m looking at using - it seems like replacing the lights is a good idea, I’ll see f I an get my missus to find out who our local SCB bod is
i may keep the E27 bulbs in the bathroom - currently they are smart bulbs linked to a motion sensor so that come on automatically at a low brightness during the night. The bathroom doesn’t have air on and has ventilation to the outside so hopefully the additional reduction in thermal efficiency won’t cause too much of an issue