Sorry for resurrecting this... Just wanted to know if anyone knows of a "folding" fire door?
Can't be 100%, but have never come across folding fire doors and doubt they are available.
It's not just the doors themselves which have to be fire-resistant, but the frames and seals. To be an FD30, a door needs intumescent strips, and may also need smoke seals. I suspect it doubtful that seals would work effectively with a folding door.
As regards your internal layout, you would normally have two options;
Either 1. keep a protected entrance hall, which is an enclosure where all the walls are 30 minutes fire-rsistant, and doors at least FD20 - though these may not be available now - but self-closers need not be fitted
or 2. plan the flat so that no point is further than 9m to the flat entrance and have the kitchen remote from the entrance (it doesn't seem to be in your case).
In general, fire regs can often be difficult to interpret, every situation is different and many inspectors and fire experts will come to different conclusions. If you are not happy with what your BCO says, get him to explain, with the Approved Document B before him, why he has come to his decision.