OP
Engineer54
As has been suggested by Malcolm and others get an electrician in to sort this little lot out for you. Not any electrician but one that is old enough to know how to deal with these braided cables and the metal conduit installation.
As this is probably a block of garages, it may be prudent to talk to the other owners of these sold off ex-council garages with the intention of giving the block a complete rewire. As if you are in the middle of this block, you are going to be stuck with those old braided cables supplying your garage. They will then be a source of failure at anytime in the future, especially if someone else (other owner) starts messing around with them....
As this is probably a block of garages, it may be prudent to talk to the other owners of these sold off ex-council garages with the intention of giving the block a complete rewire. As if you are in the middle of this block, you are going to be stuck with those old braided cables supplying your garage. They will then be a source of failure at anytime in the future, especially if someone else (other owner) starts messing around with them....