Peter Taylor wrote:

If the roof was part of the original house then it
won't, even though it is open-fronted.

OK that is the case.

Such is the clarity of the legislation passed by John Selwyn Gummer
as Environment Secretary and John Redwood as Welsh Secretary

I just had a look at the statutory instrument, it does seem less
afflicted by legalese than other Westminster products I've had the
displeasure of perusing.

Whatever this tells you, you'd be very unwise to just go ahead and build
it without checking with the Planners

Don't worry I don't take legal advice from usenet, the porch was built
by a previous owner, I was aware of the 3.0m^2 number, but not sure what
was included within it, it would have been over if EFGH counted.

Is there anything which stipulates that the original external doorway
can or can't be subsequently removed, thereby making the porch become an
enlarged hall?