it is fairly obvious from paddy's first pics that the cu is fixed to the wall and then there are bits of timber and doors and shit stacked up on the wall when he's taken the picture

why are people thinking that he's biult it in there so that even the flap can't be opened is beyond me

i'll get some pics of mine up later when i get the dongle thingy sorted, but you need to get proper electrics sorted first and foremost, is probably worth your while to do a full rewire now you have an issue and consider any further work you'll possibly do in the future to the property so that you can have additional capacity in the unit for afterwards

our house was built in 1929 and didn't even have a switch to kill thepower to the house, the mains cable went straight into the meter and then spread out to the various different pull switches you see in old school horror film that mad scientists use to power up their franenstiens