I respectfully beg to differ. There are massive chunks of Scotland which have no cellular reception at all. There are many places where there is service from some-but-not-all providers. Of those places, there are a few where the service is glacial in performance.
Example: if you stop at The Green Welly Stop in Tyndrum (FK20 8RY), you'll have coverage from only two of the mobile networks. Vodafone and o2 have a coverage patch there. Have a look at the coverage maps (bidb.uk aggregates them all). It's absolutely patchy, and certainly not contiguous.
