I recently moved into a house and heard a dripping noise coming from the airing cupboard. Worked out that a pressure relief valve was letting water through and had a plumber come out to look. He said the expansion tank and relief valve we'd to be replaced, the only snag is that having taken photos of the parts and gone away, he's been unable to source the valve because of the fitting it has, which appears to be a bayonet or similar. I'm going to contact the builders of the house to see if they can help out, but can anyone identify this part or tell me the name of that kind of connection? Haven't had any luck searching so far but I know little about plumbing yet.
The got water tank is an Ideal Thermstore and Ideal have similar looking 1.5bar valves, but all the ones I've seen have threads for both connections.
I'm in England.