I’ve been following the threads on the smell of gas in motorhome bottle cupboards and until now havent done anything about the gas smell we have always had in ours. Since daughter has been using our motorhome recently and pointed out the gas smell, I bought some leak detector spray from Screwfix and checked the bottle connections and found a slight leak at the main connection to the gas bottle. Our local caravan/ camping suppliers had the hose connections (pig tails) in stock so replaced the pigtail and now all is ok. I found the domed face of the old pig tail had some slight scratches/ dents probably where the brass joint had hit something on bottle change and this was enough I think to cause the leak. Apart from modifying a spanner to fit the nut at the motorhome joint replacement was very straightforward - cost about £12.50. If you smell gas, check the face of the domed connected to cylinder on the pigtail to se if it has any scratches or dents, and replace if necessary.