Thanks chaps.

is already plotting luggage domination. She seems strangely unhappy about the mere 20% increase in volume achieved compared to the old Samsonite that was used in the past.
I believe there are fitted bags for some panniers.
Paul that's an impressive piece of work

The use of P clips is a great idea. We use them all the time on aircraft, especially those with steel tube construction like the Auster and the Kitfox. Amazing what they'll hold. But, as you've hinted, one of the universal laws: Luggage Expands to Fit the Space Available - means you'll need to start planning for the next model