I didn't commute to Warwick, but my last uni was about 3-3.5 hours commute via tube and train. I did history and was writing my dissertation (and also had just come back from Erasmus) so I had the same thoughts.
It becomes very hard to motivate yourself to go to all your lectures. Especially if they're 9am - the trains were much slower at this time and I'd be leaving my place around 5am. There was one module I didn't attend any of my lectures for, just did my own studying. Turned out that module was the only one I got a 2:1 for so I suppose I didn't make up for the missed lectures.
It turned out okay overall though, I saved a lot of money which helped me pay off my overdraft and will help me get by this year with my MA at Warwick. Got a first which I was aiming for. It also proved quite useful to have the LSE library 45m away since its got a pretty impressive selection. Living with parents and writing a dissertation can be a bit stressful though.