"Peter Crosland" wrote in
:

I've had problems with this, and I am no expert but it is more
possible to get councils to agree if you are prepared to add some
species of reversion clause (non-technical use of language here) such
that in so many years or
on
change of ownership the land reverts to agricultural use. I don't
think
this
is advertised but it certainly does happen.

Certainly there is a mechanism to do this. One of the prime reasons
for restricting extension of gardens into agricultural land is that
there is a presumption in favour of development with the domestic
curtilage.

Ah, I see. I didn't know this before I posted something a few moments ago.
So this explains why the councils fear it as the thin end of the wedge,
then!

Therefore if the garden is extended without restriction it
could open the way to more houses being built on land that would not
otherwise be permitted. Usually a legally binding agreement is
required that prevents the land being separated form the existing
house.

I'd have no problem with that.

Chris