You don't need a rear rack to just hold the Dry bag on. The width of the bike at the back is quite sufficient to safely strap a bag onto provided you use sturdy straps. The covers over the silencer prts of the end can are also quite sturdy and if your bag droops slightly onto them the heat will not transfer and burn them. When I first got my Ten I went to the Derbyshire meet of the XT club with soft panniers on and just let them sit on the heat shields. No problem.
To get a bigger rear rack you could contact Peatbog on this site or if you really want something quick why not try Adventure-spec as they also have a rear rack. They aree are not that far away from you and you could have a ride up to them and see what other goodies they have.

SteveD

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