Is this legal (electrical work)

MyRealNameToo

Ectophile said:
A 17th Edition era plastic consumer unit in good condition may only be a C3 as there's nothing really wrong with it.  An old 13th Edition era Wylex box with only rewirable fuses is likely to fail (even if it's a metal one).

Which has nothing to do with it being plastic (as you say, it may not even be plastic) which was the sole basis on which it was stated it needed replacing. As I said there can be other issues with it beyond it being plastic that may mean it needs changing and then if its changed now it does have to be one up to current code which most likely will mean its metal (though have seen others suggest plastic can be compatible with suitable fire suppression additions) 

greyteam1959

Get a quote from somebody else is the best way to go.