hello,
Im currently at oxford doing the intergrated, i have 30 hours on a PA28, has helped me great amount with knowing simple things like circuits and what happens when you put in a stage of flap. Questions are sometimes based as if you already have knowledge of flying, for example some of the guys in my class have no experience and found it hard to grasp what the questions was asking. Basicly it definetly wouldnt hurt to do some hours but maybe nt a full ppl, theories you get tought may not be the way oxford want to teach you and so you are left having to relearn, that goes for both planning and mapping flights, to your training in good year!
Good luck with it all, dont hesitate to message me if you have any questions, just finishing phase 2, jaas next week, then...... PHOENIX!!
Safe flying!