Hi there,
This is a pretty good one for me as I'm from Bristol, attend Exeter studying law and also extensively looked at Nottingham and also opted for it.
First of all, ignore league tables. They vary because there is no definitive "better" uni. The difference between the three is pretty negligible and no employer in the firms I presume you're aiming for is going to favour you because you chose one over the other.
Think about the other factors that matter to you - Exeter is a smaller city and a campus uni; Bristol is bigger and a city uni; Nottingham is a decently sized city but also a campus. Nottingham is in the Midlands area, while the other two are down South. Do you want a campus uni or prefer the city life?
Those are the factors you should be looking at; I'm happy to answer any questions.