I bought a second hand 7ltr 300bar cylinder a little while back, and recently noticed that the open/close plastic knob tends to turn on its square drive spindle (obviously been over tightened at some point), so I can't always close the valve fully. I took the knob off (spindle is threaded at the end, one 6mm nylock nut) and the square drive hole in the knob has rounded. So I want to buy a new one and can see various versions, most of them for just a few quid. I was going to go with best Fittings, but when I took the Best Fittings one off my other bottle to try it, it would not fit. The square drive on the Best Fittings version is smaller. The one I want to replace is a 7mm square drive.

The only hint at a manufacturer I can see on the valve is the logo of 3 stars in a triangle:

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I've done a bit of googling but can't find who this is - does anyone know ?