The message
from "JK" contains these words:

The property behind mine has a large makeshift shed. Because the level of
their garden is about 2ft higher, the height is about 3m above the level of
our lawn. Now he's saying he wants to build it in brick, ie rip down the
shanty-town thing that is there and replace it with a brickbuilt outhouse.
Anyone know what rules would govern this? It seems a bit excessively high to
be built right up against my fence, and shouldn't he have toget planning
permission?

I'm worried because our house is currently being sold, and I don't want to
get into a dispute which might endanger the sale, but on the other hand, I
can't ignore it.

You're right that if you are involved in a current dispute with a
neighbour, you are obliged to reveal this if a purchaser asks (and they
will, if their solicitor is competent). That doesn't necessarily
endanger the sale.

You might also get into a legal tangle if you fail to notify a buyer
of some relevant information he can prove you knew about; such as when
his new neighbour says "Brick monstrosity? Old JK knew all about it
before he sold up, surely he told you?".

Making a simple enquiry at your local planning dept about planning
restrictions, is not a dispute with your neighbour. When your buyer asks
about neighbour relations, you can (truthfully) say you have never had
any problems with your neighbour, and pass on what you've found out.

Janet