Any normal internal door has heat resistance for the required duration
stated in the fire safety regulations, and only need to be self
closing to suit building regulations. So go and buy your doors and
fit self closing springs or arms to them.

Is this right? I have some 6 panelled Victorian internal doors. Would they
meet building regs if I put a British Standard closer on them? Sounds too
good to be true... I thought they had to be 25mm thick...

Colin