As an alternative to KTM it might be worth looking at a Honda CBX500 with Rally Raid kit on it John. I would imagine that would also do for your other planned trips and would also work well for getting about in that there London!
Top stuff for going back Mark, I'm sure you'll have a fantastic time. I would love to have another go at the trails we did, but want to get some more off road skills and experience before a revisit in the hope I'll spend more time upright next time
Looking forward to your trip report in 2017