Whilst I have no concept of the pain and difficulty involved, the thing which concerns me about this is that it's intended for use on a LEJoG. If it was a relaxed tour, with no real plans other than having a good time, then the extra weight and effort of suspension wouldn't be such an issue.
If you need to cover 900+ miles, though, then the focus is (I would expect) more about getting it done as easily as possible.
Along with more info on the bike, I think it would be good to get an understanding of the planned timetable. If you are doing it on an Apollo FS over 2 weeks, then that's probably something which the bike could handle easily. If you have a punishing schedule, say an 8 day timetable, then the bike would be an issue.