It seems silly responding to such an old post, but I was looking through the archives, thought I could help and maybe you have the post set up so as you receive an email telling you that there was a reply to your post.
Basically, I remember hot summers running through the sprinkler in my parents back garden. I also remember the year that the garden benches began to sink into the garden and I didn't want to play out there anymore. By the following summer it was literally a bog. My dad is a builder and as such knows the right people in the right departments of the local authority and water company to make sure everything was checked and double checked with regards to the underground pipes. They were adement there wasn't a problem, whilst my Dad, digging two foot trenches in the garden, was adament there must be. FINALLY, after the fourth year of a boggy garden my dad paid a lot of money (couldn't sell the house in that state) for a surveyor to inform him that there was a large pipe running under the garden from the local milk factory, which had surprisingly sprung a leak. Within a year the garden was back to normal, insurance claim accepted and house on the market. Moral of the story which I use in all walks of life is not to listen, not to trust the experts and never give up! If something seems wrong - there is. Investigate, investigate, investigate.
Good luck!
