[Robinsond22000]

I would:
1. Question why you have 2 meters, make sure you are not paying an extra standing day charge.
2. Go for three phase charging, the price difference for the Zappi 22kW is not that much different from the 7kw, dependent on your cable run. It will future proof your install and balance out your loads.
3. Get an electrician to install the chargemaster, but use a 5 core cable utilising only 3 cores and earth the other 2. When you need to upgrade, replace the chargemaster for another 22kw zappi.

 

[Robinsond22000]

Take care balancing the loads across the phases - most EVs charge on just a single phase (L1) and it would be very easy to end up drawing 64A from a single phase which may be close to the limit. I have seen some charge point deliberately wired L2 to L1 to avoid this issue.

Excatly why you should go with a unit that has load balancing intergrated into the unit like the Zappi.

Bit off track, but do you think its possible to install a TP Zappi and wire to SP?