I had previously, perhaps in error, told her that it would involve a lot of mess and re-decoration for the cable to be chased into the wall. Either that or she would have to suffer trunking attached to the wall.
However, she has had an estimate for the job and mentioned my concerns. The plumber guy said that his sparky mate could drop the cable down the cavity and straight into the back of the consumer unit... No mess! I assume that the electrician would be able to self-certify his work under Part P.
Now, somewhere inside me is the notion that the dropping of cables down a cavity is considered taboo.
There is, at present, no cavity insulation so it would be a relatively straightforward job and I can't really think of many reasons against it except that any future cavity insulation would degrade the current carrying rating of the cable. Also the vertical drop would be unsupported, but at about 3m, I don't think that this would be a problem for 6 or 10mm T/E.
Perhaps I just have this misguided idea that it is a no-no!
Any advice appreciated.