As above, really. The prestige of the school at this point matters significantly less than the ability of your supervisor to cater to your research interests. It's more about the standing of the individual than the school once you get to PhD. Eg. if I had a choice to go to Oxford under Rupert Gethin or Jan Westerhoff but their research interests did not align with mine, the better choice for me might be to go to Lancaster under Ram Chakravarthi.
If possible, try to get to know some prospective supervisors beforehand. It is imperative that you get on, you will work very closely and any friction can make the whole experience a living misery.