Theo wrote:

The train of thought was that, as part of current works, I'm thinking of
putting in a circuit for EV charging. I don't have an EV, nor do I have a
space on the CU to fit it, but working on the 'materials are cheap, labour
is expensive' principle (especially when you've made good on top of
everything) it's only the cost of the cable to do it now. The CU
replacement is likely to happen in the medium term (which would include
wiring in this cable), which just leaves the (relatively limited) external
wiring for the EVSE.

And then, scope creep being what it is, I was pondering what the uplift to
three phase would be.

If you want maximum future proofing, put in cable that can handle
connection to one or more current transformers for "smart" charge points.

https://www.doncastercables.com/cables/17/77/EV-Ultra/Power-and-data-connectivity-combined-in-one-cable/