I am assuming this is going to operate as intended like this and will be OK until I get another spark in. Obviously needs putting right and anyone working on either system needs to be made aware.
Apologies, getting used to new forum. Figured it out now.
Cable from mcb and main switch feed pen protection in its own unit directly above. 6mm2 3 core swa goes from charger CU through wall direct to charger. The armour hasn't been earthed either end.
So had an electrician round to fit car charger, charger working ok but was a bit of a rough install so decided to take a look behind the curtain in the CU. The charger is fed from a separate CU above main board for the house that is powered from the mcb next to the main switch. That neutral wire...