Am I being naive?

Hi guys,
I have been given my offers for maths and computer sci and I'm really in a pickle. I've narrowed it down to Bristol and Loughborough, because I was so impressed with both of them especially the lecturers and courses. However, they do seem a world apart.
One thing that is concerning me, is that Loughborough's entrant grades are so much lower ABB compared to bristol A*AA. Is this a sign of the difference in their educational standards?
Also, as bristol has a more prolific history than Loughborough, will it look better on a CV having a degree from them?

I know it's probably not something to worry about, but I can't help myself! :')

Thanks