As an integrated student at Oxford you'll be doing the first hundred hours of flying in the USA. So, as F3 suggested, commute for the groundschool and rent during the UK flying phase. I'd say that it's essential to be close at hand for the flying so that you can react to the programme changes which are a fact of life at any school. You also need to be bright-eyed and bushy-tailed on the early starts and a long drive before won't help. As well as that, going down the pub with your fellows gives you a much needed shoulder to cry on when a trip goes badly - you'll then find that everyone else has a similar horror story!