Go to Surrey...
I just finished my masters there, excellent University.
Pros:
Its a LARGE University with excellent facilities on campus (Doubt Napier would come any where near Surrey's, with all respect).
plenty of activities taking place on campus
Plenty of student accommodation options whether on campus or at the Unis Research Park (new accommodation, very VERY nice, common rooms with big screen LCD tvs, table tennis, proper laundry rooms, and endless fields for playing sports... oh forgot to mention the larger sports centre which is as big as the whole campus itself!
bus routes take you from inside ur accommodation complex at research park, takes you to Uni, train station, and town centre in like 10 mintues drive to the furthest distance.
From Guildford station its only 40 minutes to London waterloo... I've been going to london every weekend and had the best time of my life.
town centre has everything you need and you can walk there from campus, cinema is across the street from campus, tesco is in the middle between campus and research park..
large nationalities diversification... i've never been to a uni with such a large mix with people from everywhere in the world and all speak highly about the uni reputation (which is why they all ended up here of course). so if you're international student and yearn to your home country, rest assured that you'll find people there who will ease your homesickness.
Also if you're international student, the Uni is only about 30 minutes by taxi from Heathrow airport (and the ride costs about 35 pounds) which isn't much when compared with other locations.
I'd say go to Surrey and don't bother thinking about Napier.
I don't know where you're from, but to me as an international student I'd choose Surrey over The University of Edinburgh and Oxford!