How and where are you washing your electric car?

On a somewhat serious note, I'd probably be a bit more apprehensive about a high-pressure underbody wash one an older EV than on most other cars.

All EVs have good IP ratings, but over time, gore vents and seals can degrade, and a rating is not a guarantee for life that the part will remain waterproof. Additionally, like any other car, undertrays can be damaged and get lost over time, and connectors might not be seated perfectly by a mechanic who removed it for some reason or other.

Just to add, this is not anti-EV. All cars can suffer similar, but have more sensitive, more expensive electronics sitting lower down increases risk.

This is an interesting article about how water spray is simulated, and is applicable to how the location of electrical connectors is decided in the design phase - to keep them as dry as possible.. https://www.autonomousvehicleinternational.com/features/why-simulation-of-vehicle-water-and-dirt-management-is-important-for-adas-development.html

meguiars or turtle wax better in consumer products available in Halfords

There used to be a very good detailing thread here a few years ago but, sadly, it seems to be gone.

Rather than spending a fortune in Halfords, try D&D Detailing or Autopia who regularly have sales. Make sure that you get a wash mitt, two buckets with grit guards, shampoo, polish and wax. After that, you can get a foam gun, pre-wash, tyre gel etc. It's up to you.

As mentioned above, Collonite Insulator wax is the business. Put two coats on after a wash and polish and it will keep your car protected for several months. A bottle will last you several years.

Two buckets ideally:) but can get away with one if careful