There are special alkylate fuels like Aspen for this specific purpose, but the cost (£4-5/liter) might be a bit prohibitive for use in vehicles.
Premium fuels are still the best option I think, for instance Esso claims that their Synergy Supreme+ is ethanol-free in most of the UK: "Although our pumps have E5 labels on them, our Synergy Supreme+ 99 is actually ethanol free (except, due to technical supply reasons, in Devon, Cornwall, North Wales, North England and Scotland)." (https://www.esso.co.uk/en-gb/fuels/petrol ). You should be able to find out if the premium fuel of your brand of choice contains any ethanol.
If that fails, removing the ethanol yourself is simple but a bit of a hassle, although less hassle than periodically replacing your fuel system components I think... See https://www.youtube.com/watch?v=opPZD8-2fLk&list=PLXaf5EqG6RkflW4MU1f1Cc5NJjcB0JtSl&index=4&t=16s for the principle, just enlarge the scale.
Avgas will work fine too but might be prohibited for vehicular use, although the chance of someone actually checking what sort of petrol you're running is quite small I guess? I think it does cost substantially more than premium car fuels though.