Toilet will flush 2/3 times with a healthy fill. However after 3rd flush does not fill again.

[AL Hughes]

Push button cistern.
Toilet will flush only say twice.
Filling the cistern after very well.
After 2nd flush water stops filling cistern.
The left hand side has a plastic tube say 4 inches long from where the water comes. Along side is a small branch with a blue button with two arrows.
By luck I have found that pressing gently down on the branch the water flows into the cistern and can flush again. This is an enclosed cistern so cannot keep taking the wood off.
I think the valve is sticking.
How can I cure this please?
This is a new toilet but has not been used for a year, just been completed.
New flat.

 

[snowhead]

Sounds like the float is sticking and it won't help with all the rubble in the bottom.
It looks like the cistern has been open and sprayed with paint.

If the "Button with the arrows" is the blue rod with the cross in the top for a screwdriver, that's the adjustment for the float below, looks also to be blue.

Probably this;
1/2" Toilet Cistern Side Entry Inlet Fill Valve Brass Tail | eBay

 

[AL Hughes]

Sounds like the float is sticking and it won't help with all the rubble in the bottom.
It looks like the cistern has been open and sprayed with paint.

If the "Button with the arrows" is the blue rod with the cross in the top for a screwdriver, that's the adjustment for the float below, looks also to be blue.

Probably this;
1/2" Toilet Cistern Side Entry Inlet Fill Valve Brass Tail | eBay

 

[AL Hughes]

Sounds like the float is sticking and it won't help with all the rubble in the bottom.
It looks like the cistern has been open and sprayed with paint.

If the "Button with the arrows" is the blue rod with the cross in the top for a screwdriver, that's the adjustment for the float below, looks also to be blue.

Probably this;
1/2" Toilet Cistern Side Entry Inlet Fill Valve Brass Tail | eBay

Thanks for help. The cistern has no cover. About a foot above this is a long plinth which acts as a shelf which really should not be removed unless the toilet fails! Will speak to the snagging contractor. Will have to look closer to see if there is a screw adjustment on the side arm.
Thanks again.