A neighbour recently told me that she could hear an underground stream
flowing beneath her garden, and suggested maybe it flowed across mine
too. Then someone sent me an old map of the West Hampstead area in
London which shows an underground stream passing more or less along
the boundary between the bottom of my garden, and the field next
door. If the stream lies on my side of the boundary and isn't too
deep, it might be nice to uncover it and create a natural pool. I'll
need some kind of survey to pinpoint it, of course - has anyone got
any experience with reliable people/companies who do this kind of
thing ?

Ken