Cooker Hose Adaptor for UK Cooker

Is the gas bottle intended to be inside the house or outside? There are two different types - the lightweight plastic ones (with a snap fitting for the détendeur) and the metal ones are blue and grey with a screw type détendeur which are propane. Butane is not recommended for outside storage.
The French détendeur for butane is explained here:

The better flexible hoses are preformed and usually available from supermarkets and brico sheds. It’s difficult to see how the hose is formed from your picture but the preformed ones, whilst more expensive, are a better bet and designed for the job.
This earlier topic might also be a useful reference…