I am quoting for a job to fit a new cooker cicuit into a kitchen, There is no RCD protection to any of the house, The man living there is an old chap who cannot afford a new board (the board is fairly modern/good condition with mcbs) now under 17th edition the circuit I am fitting should be rcd protected I will try and locate an rcbo if poss, if not should I fit an rcd into the main tails (is this the cheapest option ?) as this will rcd the whole house -( nusiance tripping !! )or can I simply recommend a fuse board upgrade on my test certificate ?