OP
NadHuh
so the so called electrician who ran out of 3 core should be sacked and replaced by a spark who knows what he's doing. did he run out of earth sleeving , so replace with a bit of tape? run out of screws so a couple of nails will do. FFS. use the right gear for the job or leave it to someone who can.
What's wrong with using two twin and earths for something that needs 3 core or 4 core? Apart from it being expensive?