"How far are the cables from the corner ?" - About 10" or so. The cable was always there, on the surface of the tiled wall inside a square plastic conduit. All Ive done (apart from 100% gutting my kitchen) is putting the cable out of sight under the plaster.
Your use of the term "all i've done" makes me think you don't realise the implications of what you are doing. A cable in trunking on the surface is not considered "concealed", a cable burried under the plaster is considered "concealed". The rules are much stricter for concealed cables than non-concealed ones. You are making a cable concealed that was not previously concealed and therefore you need to ensure that it is still compliant afterwards.
You have three main options for running concealed cables in compliance with current regs.
Option 1: run them in a safe zone AND ensure they are protected by a 30ma RCD
Option 2: run them in earthed steel conduit (capping is not considered sufficient)
Option 3: Run them in a special cable type that has a suitable earthed metal layer such as MICC, SWA or flexishield.
there is also theoretically two other options
Option 4: bury them more than 50mm deep.
Option 5: run them in a safe zone AND ensure that the installation is under the supervision of a "skilled or instructed person".
But in practice option 4 tends to be impractical because of other considerations (You need to be very careful about structural considerations if you cut a chase that deep) and option 5 tends to lead to arguments over the definition of a skilled or instructed person and even if the installation is under the supervision of one now whether it will stay that way.
So assuming the cable is ordinary T&E then before you proceed with concealing it you need to determine whether it is in a safe zone and whether it is RCD protected. There is a safe zone in the corner of the wall but it only goes to 150mm (just under 6 inches) from the corner. So if your cable is 10 inches from the corner it is not in it. If the cable is feeding an accessory directly above it then it will be in the safe zone formed by the accessory (note that the safe zones formed by accessories only apply to cables feeding that accessory) but otherwise you have a problem.
