How old is the house? This would be a guide to how old the wiring is, unless its been rewired since.
Generally if 70s or later, there shouldnt be a need to re-wire, UNLESS its been bodged around with in the past, which does happen. Before the 70s there could be quite a few reasons its beyond end of life VIR (Vulcanised India Rubber) cables, no earths to lights, copper clad (Aluminimum). If 80's or 90's then on quite a firm footing that it shouldnt need ewiring (unless of course, been messed around with)
You would quite likely require some other remedial works at the same time, main bonding(could be missing undersized on 70s install, should be if dating from 80s/90s ), or fault repair (if any are found)
Is your wylex fuseboard brown or cream?
Make sure you ask for some spare ways to be left, for loft conversion. Also avail yourself of the difference between a dual RCD board (all the cirucits are split across two RCDs, so if one trips, you loos half the power, it should be split sensibly do upstairs lights are paired with downstairs power, etc). Or an RCBO board (Uses RCBOs instead of MCBS, which are basically an RCD built into each MCB, so you only loose the affected circuit). Or you can for bit of both, some dual RCD boards are what are called Hi-integrity boards, that is that they can have some circuits that are not on either of the RCDs, you can then fit RCBOs in these ways for circuits you don't want to tripped off by a fault on another circuit(eg. home server, etc). Full RCBO protetcion ovbiously costs more than a dual RCD board, but maybe not stupidly more, ask for a price each way and decide if its worth it.
