It might have a Pride, but Exeter is going to be a much smaller marketplace than anywhere with a more significant scene. On the plus side, you may be one of very few options for people who are looking for someone there rather than one of many hundreds in London.
It's a long journey there, especially if you go the cheaper ways. Realistically, a big chunk of the gay market in places like London is 'I want sex and I want sex now' rather than advanced bookings, so even Herts is going to be out of the way. Plus before making any long journey, I'd suggest you have a search here for ways to ensure that it's not a fruitless one.
Yes, see what the magazines you can pick up in Exeter allow in terms of advertising. The national ones can tend to be too expensive on the grounds that they have a large readership, but you don't care how many readers they have across the country - you're only interested in the ones in the South West.
Who doesn't have a profile there?
Alas, yes, if they find you hustling in the escort area without paying, they will ban you. You'd need to check some other profiles to see if you can get away with mentioning it in your regular page, or if you need to do it more discreetly.
Oh, I'm not saying AME is a waste - only you can decide that. What used to happen is that they used to yoyo from top of the Google listings to nowhere as their latest dodgy bit of search engine fooling was discovered. If that's ended, they may well be more consistently listed, but geography will remain a problem.