Electricians - am I being mugged?

[DS3R]

1960's concrete block flat, all original (and classy with it!)

Fuse boards need changing (even I know that!), most of the face plates (sockets & switches) have been changed, but some originals need replacing.

The wires are in tubes in the concrete, and setting aside that some may have collapsed, the builder says he would insist on a full re-wire irrespective that cable from the 60's is 10 times thicker than today's nonsense.

I accept regs have changed, but am not totally convinced it all needs changing. I would have thought even sparkies are allowed some discretion and common sense to say if the level of conductivity in a wire continues to be acceptable for the purpose required, then does it really need to be pulled out (or worse of course, chiselled)?

We are refurbing the whole property and I'm not going to lose any sleep if it has to be done, I just want to be sure it's being done because (setting aside the false economy of having to do it later of course), and not just because the boss of the building firm is an electrician by trade.

In the grand sceme of the overall price the amount budgeted for it is not huge, but having had fuse boards changed and wires checked by a spark on a 60's house and that was good enough for a certificate for sale, I'm struggling to see how this can be so different.

[DS3R]

As I said, I appreciate the false economy of not doing it now anyway, but if it is as straightforward as it literally can't be signed off as is, then that's my answer. I just can't find what says that where!

[DS3R]

Sounds like it makes sufficient sense then, I was just a bit put out that he didn't look at anything before declaring "it needs a rewire" (we weren't even in the property!), so he had no idea if anything had been done, it was just taken as a given and priced accordingly!

Thanks for your input guys, v much appreciate it.