Update on the water

Had a good look at the damp and think it is because of the close proximity of the water tank making the area very cold. The opposite corner has the stove to keep things warm. I am still looking at the lack of spray foam on the underside of the well deck above the tank causing condensation to drip resulting in the damp in the corner cupboard. Just need to wipe things down and see what happens. Although no leak it was the front deck floor causing the problem so I got the location right.

I found my old hand operated oil pump that I used for oil changes before fitting a permanent pump connected to the sump plug. The water has almost gone with newspaper soaking up the remaining wet surface. I removed about 12 litres and I am suspecting it was condensation built up over a long period, time will tell.