So - you’re planning a major revamp of your electrics. As cables tend to be buried in walls, under floors, above ceilings etc, you want to try as hard as possible to get it right first time, as making changes after you’ve plastered, papered, painted, carpeted etc will be a PITA.
Think hard about where to have sockets - it’s difficult to have too many, and also about what circuits to have. The items on the list below won’t all apply to you, but they are worth thinking about:
Plus any peculiarities brought about by your house layout & construction - e.g. in mine because of solid floors and where the socket circuits run, I have a radial just for a socket in the hall, the doorbell and the porch lights.
Unless you want to go to the expense of RCBOs throughout, the CU should have at least 3 sections, 2 on RCDs and one not into which you can install a mix of RCBOs and MCBs.
It can be a good idea to put all wiring in conduit for ease of future changes. And if you specify metal conduit for switch drops, or BS 8436 cable, it removes the need to have RCDs on lighting circuits (apart from bathrooms).
If you live somewhere where supplies are dodgy in the winter, have the lights, the boiler supply, and a socket in each room wired to a separate CU, or a separate section in a large one, that can be supplied by an emergency generator - lights, heating, TV and a kettle/microwave make life a lot more bearable.
Flood-wiring with Cat6 or Cat6a cable is worth thinking about.