I copied/pasted the web address to see the photo.
You need to push the collar in, with a screwdriver or similar, and then the hose should pull out.
If you need more, or replacements, they're 12mm pushfit - not the more usual 13mm pushfit used in domestic plumbing.
When you reconnect, make sure you push the hose fully home - beyond the first point of resistance - otherwise it'll come out under pressure - and ALWAYS ensure you fully test it at home BEFORE you got away - got the teashirt !!!