Looked at the Knox but, as you guessed, decided it wasn't big enough. After a lot of searching around I ended up ordering a Pro Force Tomahawk pack from Highlander (Not in DPM though).



Decided on this over a usual walking based rucksack because of the difference in size ratio's. Most walking rucksacks are tall and thin, great for walking but a hindrance when it comes to trying to strap the rucksack to the bike (the preferred method of carrying it ). The tomahawk is more of an 'old fashioned' squat shape, which should make it easier to strap to the bike.

Hopefully going to get away for a few days this week to give it a bit of a road test, both carried on the shoulder and strapped to the bike.