My choice would be based on distance from London (using public transport), cost of flying and social atmosphere in the club.
The
West London Aero Club is a long established club (50+ years) with a good reputation and a friendly social atmosphere.
Probably the best clubhouse in the country.
Grass airfield (I believe the biggest in the UK) with 3 runways.
No home landing fees. *
Frequent trains from London to Maidenhead - journey time about 35 mins.
I think there may be buses to the airfield but it's just a short taxi ride - about 3 miles.
I have trained in PA28-161 so maybe get rated for PA28-181 or possibly to an Archer.
They have all three.
I'm not a member but I've been there many times over the years as a guest and have always been impressed and enjoyed the experience.
* Watch out for that when comparing prices.
And also whether the prices quoted include VAT.