Help with concealed toilet system inlet valve

[Greshamst]

Trying to get to grips with the Ideal Standard concealed toilet system in my new house.

The inlet valve keeps running even once the float has reached its ‘stop’ point. The water then goes over the max water level on the outlet valve and continually trickles into the toilet pan loudly.

I’ve taken the outlet valve out and given it a good clean, so I think it’s the inlet valve (the float and silent bag for filling the water tank that’s the issue)

My question is, does it just need replacing, and if so can anyone see from the picture if the connection is likely to be screw or push fit, before I start using brute strength on it and potentially breaking it if I guess the wrong fitting

Red circle is where it’s fitted, green circle is where it’s continuously running from.

[Greshamst]

I’m struggling to find a way to remove the fitting in red. Have tried moving the ‘collar’ as you would on a push fit system, but no luck.

[Greshamst]

Bump for visibility

[Greshamst]

miroku1 said:

They are Conceala 2 valves , really easy to change , takes about a minute !
Turn water off , un clip valve from side of cistern disconnect inlet pipe ( it’s speed fit ) replace with new reassemble, could not be easier

I wish you were right but the inlet pipe speed fit fitting does not want to budge! Just can’t get it to release, move a mm or otherwise let me remove the fitting.

[Greshamst]

Removed the outlet valve to give some more room, but the collar still does not want to move at all.

I’m a bit annoyed I’ve been outdone by a push fit fitting, but not sure what else to do.