On 27/11/2016 17:45, mechanic wrote:
On Sun, 27 Nov 2016 16:17:44 +0000, GB wrote:

Half a meter is a bit of a squeeze, but you may be able to crawl
under there to take a look.

I exaggerated - it's really about 300mm. We have air bricks in the
walls for ventilation - maybe the BG fibre optic probe thingie may
spot a pool of water.


It's unlikely to be a pool of water. Certainly not if you are on sandy
soil. Even on clay, depending on what's mixed in, there's a good chance
the water will sink in.