My remarks here relate specifically to Bosmere branded products.
Fairly recently, I purchased, via eBay, a gas bottle cover. The manufacturer was/is Bosmere and it has the following characteristics. It is from their "Protector" range, has the Product Ref: B540 and is described as having the dimensions 60cm (24 inch) high and 32cm (13 inch) diameter. It is intended for the blue Calor Gas 15kg Butane gas bottle.
ADVICE: DON'T BUY ONE! IT DOESN'T FIT!
And here's the detail. The purchased item arrived without any problem. A couple of days later I went out to fit it to the gas bottle. This is when the problems started. For anyone familiar with such gas bottles, you will know that there is a seam around the bottle halfway down. Couldn't get the cover over that seam. Would I be beaten? I would not. I sprayed the whole lower section of the bottle with WD40. Success! This enabled me to, slowly, wiggle the cover further down. Until I reached the base. Nothing I did could get the cover down over the base. What to do next? I contacted Bosmere. I learned that they "had had some problems with covers last year". The lady kindly said she would send a replacement. And she duly did. Did that fit? It did not.
Perhaps the problem was with the budget "Protector" range? Off to the garden centre. Where, by great good fortune, I found another gas bottle cover from Bosmere. This one apparently a DeLuxe version. Product Ref: C740. There was only one. I hid it and rushed home to get the packaging from my cover. Back to the garden centre. Ooops! Dimensions exactly the same. Took it to the Customer Service desk. Explained my problem. Could they try fitting their cover to a gas bottle, please? No problem. Also no fit!
So there you have it. Three different Bosmere gas bottle covers. None fit. Would I try it again? I would not.
Just to cap my experience I trotted off to a local store that supplies filled gas bottles. I explained my experience. Why did I want a cover I was asked? The bottle is made to be used outdoors. It doesn't need a cover! Went home.