Ok I've received this from Building Control -
"I can confirm that the fire door would be required between the bedroom with the ensuite and the landing. This would not be required to any other bedroom.
The relevant guidance that relates to this issue is paragraph 3.8 of Approved Document B volume 1. This paragraph advises that you can not have an inner inner room where any of the access rooms is a kitchen, which is the situation at your property. MSDC Building Control have assessed this guidance however, and agreed an alternative approach which allows this layout if the bedroom is separated from the landing with a fire door, as the risk to the inner inner room will then be suitably mitigated.
The alternative option would be to separate the kitchen from the hall with doors or partitions, as the kitchen would then not be considered an "access room". These separations and doors would not need to be fire resisting."
I'm going to have to read up about what is a room, what is an inner room, and an inner inner room, what is an access room. Maybe somebody here can give me a simple explanation?