I am suprised the boiler is on a circuit with other stuff, normally they are wired to an individual RCD on their own loop.
The Fridge freezer could be an issue depending on how much stuff you have in it, however, if you put some ice bocks in it you could probably switch it of for long enogh to move the sockets without ruining your food.
A quick fix if you do believe it is the sockets would be to re-mount the sockets in surface mount boxes close to where they are curently. This would bring them into the room and hopefully away from the damp.
Have a really good think about what you were doing when the circuit tripped.
There is a good chance of it being a faulty applience, was there anything plugged in when teh circuit tripped? did it happen when the fridge clicke on to cool or the boiler fired upt o heat?
It could also be something like a short in a cable somewhere that only shorts if stood on for example a cable in the loft under a board.
Were you doing any sparky work yourself else where at the time, could there be something else tied into the circuit you don’t realise?