Before I get officialdom involved, I'm sure someone here can help.

My wife owns a tiny property which is rented out. The tenant recently had a
problem with the consumer unit and called the letting agents whose
electrician fixed the problem but says it needs a new CU fitted to meet
current regulations. He quoted £133 in labour and £344 for parts (plus VAT
of course).

I queried the quote and was told "it will take 5 - 7 hours and the parts
cost is what my suppliers charge".

Now I'm not that dumb and I've replaced several CUs in my own homes over the
years. My query is can I do what I used to do, pull the main fuse, change
the CU then call the electricity supplier and have them inspect and refit
the fuse - or does part P plus the fact that it's rented impose more
requirements on me?