As witnessed by a number of TMers, we’ve always used a ‘clamshell’ Samsonite suitcase.
We then wrap it in a waterproof picnic blanket, then secure to the rear rack.

Lots of trips in the UK and to Europe over 18 years with this setup and no water ingress.
Case comes off at our destination and the blanket is then used for its original purpose.


Bud
4/4 - Stanley

I would have thought that Stanley would have preferred some Louis Vuitton wrapped in the LLB's mink stole

I too am a Boot Bag fan find it very practical and adaptable for large or small loads. I put squishy holdall type bags inside the Boot Bag I can then pack what is needed daily in one bag and what is needed on a more limited basis in another bag which means not having to rummage through one big bag every day. Have used the Boot Bag in every kind of weather with no problems kept everything dry.