Thanks for all the info.
The Hepco & Becker kit arrived today, and is now mounted.
The 5Kg weight limit on a 40 Litre Top Box (that is rated for 10Kg) is a serious limitation. It means I can only ever really pack clothing in it for journeys and store helmets and gloves when parked up.
The other issue, and perhaps the most worrying is if a pillion uses the top box as a back rest...
It could end in tears.
Not the end of the world, but definitely a limitation that means I would have to recommend shopping elsewhere for luggage systems. It looks like the Givi System is the way to go. It's just a shame I kept my old Hepco & Becker luggage from my previous bike or I would have probably just bought a Givi system.
I should also point out that the Hepco & Becker luggage when mounted on my previous bike was faultless. I see this as Suzuki's fault for making a mounting point out of tissue paper.
Oh well, at least it looks good!
Jon