Grounding Water Supply for Chargepoint

I’m getting a ‘proper’ chargepoint installed in a few weeks but in order to do so I needed to get quite a lot of my electrics upgraded, including earth bonding the mains water supply.

Trouble is, the water supply is in the opposite downstairs cupboard to where the mains electrics are under the stairs, and we have concrete floors, no floorboards. It will also be a pain to go over the top as we’ve just had new carpet fitted and all of that would have to come up.

Has anyone had to have anything similar done and/or can anyone recommend a good electrician in the Essex/London area to complete this job?