I'd also put my money on Hawarden. Liverpool is too busy in my opinion for PPL training. You'll spend a fair bit of money sitting at the hold or orbiting. I did and that was 15 years ago. That being said ask the schools how they charge. If it's airborne plus say 10 mins at the start then 5 mins after you're familiar then that mitigates the holding point money trap but not the orbiting one.
Hawarden is decent, but if you're doing it in summer at weekends you may find the opening hours a pain. Otherwise it's a quiet airfield with good access to the south and wales for nav exercises. The airport can be a law unto themselves at times, and don't dare even think about going airside without a Hi Viz. They'll know you thought about it!!!!!
How far would you drive? I'm not sure how the situation at Barton is these days. Or even Sleap? Though that may be a bit far.
Jump in the car and visit as many as possible. You can't beat face time with the school to gauge how you'll feel handing over your hard earned to them.