NotMe wrote:
I was under the impression that as long as a kitchen - regardless whether it
has windows, or not - has a volume of at least 10 m^3, a gas (open flame)
hob can be used there.

I was today given a different advice by a plumber friend (who is not corgi
qualified BTW), who claimed that this was against the building regulations.

My kitchen is 10.3 m^3 (carefully planned to fit), has no windows at all
(just a door into the hall), and I intend to install a gas hob there next
week. I also intend to have a gas combi boiler there, fitted to an external
wall, with the flue going through it to the outside.

Can anyone enlighten me as to my situation? Couldn't find anything
online...

Well you obviously didn't check the Font of All Wisdom, the uk.d-i-y
FAQ, did you? :-)

http://www.diyfaq.org.uk/contents.html

See the Gas fitting section: "...in the case of a gas hob the room in
question must have a door, window or other vent that can be opened
directly to outside air and the room must have a volume of at least 10
cubic metres"

....which I interpret to mean that your plumber's correct, don't you?

David