Yeah its no big deal, I thought I would have a problem too because I a few years ago I went backpacking round Africa for 3 months living in a tent, obviously I was able to produce absolutely no proof of where I was or what I was doing, but it turns out all you have to do just have to write on the form what you were doing and then get a mate to verify it. As far as I'm aware any old punter will do as long as you claim to have known them for over 5 years, it could be Abu Hamza for all they know or care.
Good on you DfT, al qaeda will NEVER figure out how to get around that one, you've stopped them in their tracks