We use a boat bag.There is a Mog specific one.
Boatbag I can vouch they keep everything dry and don't block the 3rd brake light
Cheap solution is put everything in a bin liner inside a hard case.
Typo there I think…should be boot-bag.
I have used one of those for the past 11 years and it works well, with everything staying dry.I tend to put bulky stuff in it like shoes, washing gear, etc
In addition, I use a pair of “Hills Alive” cases that are tailor made to fit behind the seats. (sadly the company no longer exists)
The number of Morgan leather suitcases that you see second hand, tells its own story…look nice but simply much too heavy empty, let alone full!