After a few months of hunting , I have found some storage jars that fit well in our Eriba troll door. The plastic jars are available in most supermarkets and have peaches or fruit salad in them. They fit the 2 lower shelves perfectly without distorting the bar. Airtight and waterproof if the door should be open without awning cover in a British squall! We keep tea bags ( PG and herbal), coffee pods, pegs, mend it stuff, rice and pasta when away and anything else that will fit!
I have posted a photo in the photo section in the 'doors' section.
Hope you find it a useful idea.
Tin tent knitter