I was thinking of using a 3 SIM card when touring the UK. I have one of these mifi things sitting idle and figured I might be able to get some use out of it with one of these SIMs. They seem to have an unlimited data plan for £15 per month with no contract. Couple of questions. Is it really unlimited? Are 3 any good in the kind of remote locations where you get camp sites are will I not get a good signal? Any advice much appreciated.