Thanks for the advice. Much appreciated.
I'll try getting some professional advice. Not sure whether a damp expert or an estate agent is the best bet though!
I'm part way through laying ceramic tiles onto a concrete floor of the utility area at the back of our house, and I've just discovered an area where the floor appears to be quite damp in the corner next to the wall (now that I'm not far off finished!). The wall looks to be dry but there is a...