Are the sockets on a radial or a spur?
A radial socket will have 2 live and 2 neutral cables per socket; a spur will have just 1 live and one neutral (unless they are the last socket in the radial).
If it's a spur, then you can just disconnect the socket and separate/tape up the conductors. With a radial you will have to remove the wires from the socket and connect them together with an appropriate connector, then apply electrical tape round the connector.
Isolate the circuit (trip the CB) before you make or break any connections and always use a socket tester to make sure the circuit is dead.
If you have ANY doubt, call an electrician.
The sockets are spur.
I'll do what you've advised tomorrow.
The socket/s aside, I need to find out where the damp is coming from.
Thanks for your advice and help. Much appreciated.