Thank for all this guys.
It’s a long run (over 40m) so the Doncaster cable option works out rather more expensive so I’ll go separate. Neat idea for my EV point at the front which is a very short run.
I've ducting going in that can take the Ethernet cable anyway, and I like the idea of keeping it away from the mains cable.
I’ve found a source of single phase coloured cable - however my sparky is back earlier than expected and tells me to use 3phase coloured cable to save money. I’ll do what I’m told for once.