My main CU is no longer made, So you cannot get the correct RCD required. My second CU is on 16mm tails but serves the heat pump and the garage, so would draw close to the 60 amp limit. The run from the CU to the selected charger site could well be 5 metres over the 15m offered. So I could require a 3rd CU mounted on the outside wall (no room left for another CU in the house). Thus collectively, I need an idea of the cost.
The charger install won’t come from your house consumer unit, instead it’ll similar to how the heatpump consumer is connected in the electric box where the our meter tails are split in whats known as Henley blocks and each consumer is fed from that point, if that makes sense.
If any work is required to upgrade your incoming supply, this will be carried out by the DNO and will be free of charge for EV chargers, solar, heatpumps and whats ever else it determine as green for the planet.
Your house consmer unit although perhaps out of date on the spares front, isn’t obsolete where the BS7671 wiring regulations are concerned. In the future should you ever wish to upgrade, your locall sparky is the best bet.
If your house consumer unit is labled you could if wanted give me the name of the circuit and MCB rating (amps), plus that of your heartpump consumer unit, I can work out you current maximum demand and new maximum demand with an EV charger installed. If you know your incoming cut-out fuse rating, I could give a better idea of whats work would be needed, if you wanted to.