It sounds as if you have probably 'sorted' that, but the electrician will be able to confirm.I can't say for certain that I've sorted the dodgy line under the worktop, all I've done is fit a new socket and cut away the heat damaged wire to new bare copper.
Fair enough. It remains possible that that 'switch' (FCU) has become faulty and needs replacing. Again, your electrician will be easily able to ascertain that.I did check the fuse in the switch above the worktop and it was fine, swapped it for another too and same problem.
Kind Regards, John