Prices are regional so what's good for one isn't for another. It's much like motor insurance, you really need to do your own research via comparison sites and then narrow down from there.
^^^This
That said, you can put some constraints on your search if you wish. For example, for electricity I look for suppliers with 100% renewable generation, in recent years they have often been the cheapest in my area anyway.
In terms of suppliers that fit well with EV drivers, Bulb often get mentioned, as do Octopus, and I was very impressed with Tonik (I'm a previous customer but swapped about a year ago for a cheaper tariff). Ecotricity give a discount for using their Electric Highway but they have never been competitive on price in my region. Existing customers often have referral codes or you may get the equivalent through comparison websites. Zap Map also have a review of EV tariffs here:
What EV energy tariffs are available? - Zap-Map
In terms of comparison sites, I like Money Savings Expert's Cheap Energy Club but there are plenty of others.
Some people complain about their direct debit amounts changing but for electricity all that really matters is the standing charge and p/kWh, plus an idea of your annual consumption in kWh (looks like the OP knows this). Estimated annual consumption figures often seem to be miles out and bear no resemblance to historical consumption, hence the dodgy direct debit amounts. It helps if you can keep track yourself and then get on to customer services if you're running up a surplus for example.
I'm currently with Outfox the Market but they have had a lot of flak for changing rates and particularly hiking direct debit amounts just before Christmas and got swamped with billing complaints/mistakes, so I can't say I'd recommend them!
Some of these suppliers are starting to offer variable tariffs which are a bit more sophisticated that Economy 7, offering cheap off-peak rates or time-of-day variations. I've run some calculations (like the OP I use about 50kWh a week charging the car) and haven't found a variable tariff that betters the flat rate ones by a significant amount (unless I start telling the family to run the dishwasher at night and get up early to use the shower!). The situation with "smart" meters is a mess as well. Hopefully this will mature and make things like home batteries more cost effective while at the same time taking some pressure off the national grid at peak times (= less power stations needed).
