I have used a Boot Bag for a few years. A soft bag with good waterproof material. It has straps attached to secure it to the luggage rack. I have put a couple of extra press studs to improve the flap covering the zip. It sits lower than suitcases so good rear visibility. Used last September for a 10 day trip to Windermere and Scotland. I have put bin bags over it if rain is very heavy butno problems with wet clothes so far. Extra luggage is by holdalls on the shelf.
