I have been advised by the supplier I need to mount a 10mm spacer behind the upper pannier rail to create the clearance. I can't see this working as actually you also have to mount one on the lower mount too to keep it all parallel to the frame, which will then cause the lower pannier rail mount to foul on the plastic shroud/grab rail assembly and will probably require longer bolts too, which are not provided.

I'm not convinced this can ever was designed to work with OE pannier rails. But my investment in rails and boxes is far higher than it is in the exhaust, so I'm not changing those. If I can't get it to fit reasonably easily it'll have to go back as unfit for purpose. Exan themselves assured me it would fit fine.

For the benefit of others in the future I will update here with the next instalment.