In your first picture there is a damp spot under the the right hand side pipe, which is the return from the filter to the pool. Is that just because you fiddled round with the valve before taking the photo, or is water constantly getting out there? Is there a storm water drain nearby where that water could get into? Which leads me back to my first question from my last post: Is that pipe outlet on the street your normal storm water outlet, where water comes out when it's raining, or is that a pool only outlet?