Hi ben,
We’re doing something similar - at least in terms of new house and PV. We’ll only put the maximum PV in that you can do without asking permission from the DNO, so a 4kW ground mounted array. We’re also installing an ASHP for UFH and DHW. DHW will be from a 300l tank with 2 immersion points and a diverter - we may actually install an Eddi this time rather than home brew.
We are still on an old couple of vehicles, so until the oldest dies and we switch to an EV, we won’t need to charge any vehicles, although we will install EV charging points. We’ll probably go onto one of the Octopus plans with v low night time rates and use that to heat the DHW tank if it needs it. Depends on the rate I guess, the ASHP should have a CoP of between 3 and 4, so you’d need a rate less than 18p divided by 3 or 4 otherwise it might be cheaper to run the ASHP for the DHW.
As far as any battery system goes, we’re going to wait for a year or so until we have the data about how all of the systems are working.
I’d be interested to hear how you get on.
Simon