What problem are you trying to solve? I get the feeling you dont have
one.

I would check switches, sockets, lights etc, and maybe add more
sockets. I'd check it doesnt have a shower on the ring or something
like that. Beyond that its upto you how much you want to spend, but
really you're likely to see more return from spending on other areas.

Replacing a CU is far more work than replacing a fuse wire maybe twice.

You could be right, I was just getting edgy as the surveyor mentioned that
there was no modern CU there. If it works though....

Hellraiser...........