Thank you so much for such a detailed reply.
The first paragraph I am afraid just goes over my head but if the DNO sort it all good.
Yes the green/yellow earthing cable goes to the pipe connected to the gas meter in the garage and presumably the bare wire to the water pipe inlet.
The two silver clad boxes – one is for electric shower and the other is for the light switch for the cupboard under the stairs where the electric meter is.
No idea why 2 Wylex fuse boxes. Not had economy 7. Maybe previous owner had it.
So all things considered I think it’s quite positive if we can find a car suitable to my wife’s needs. As you said I will know more when a survey is done and take it from there. Thank you once again you are a star ⭐️