@slowdriver i would get in contact with Motability and ask them to get you an installer that will fit an Ohme charger. https://news.motability.co.uk/scheme-news/meet-our-home-chargepoint-providers/
Zappi are much better chargers than Ohme, which only have 4g connectivity and not solar compatable. OVO will no longer be supporting Ohme chargers either, which may see them loosing Octopus support in the future, meaning you will loose support of more intelligent tariffs if in the future you decided to switch to one 🙂