Thanks for the replies, much appreciated. Whilst the sqr mount is a neat solution; I like the points of support it offers, I am wondering whether it will be strong enough to take a camper longflap with a bit of weight in it. More reasearch I think. The Thorn option on the other hand looks pretty robust and I do like the two points of support it offers on a horizontal plane, not sure how the central lower strap attaches to it or something else. Additionally, some might find the fact that the bag is held slightly awway from the saddle a good thing, again I'm not so sure. Perhaps the 'reach around' proximity of the sqr solution is a good thing. Hmm. Either way I think I need/prefer the support offered by a rack for the Camper longflap.