Renault Espace III 2.0 Petrol - Idle Too Fast - JJFranco

Hi All,
I have a strange problem with a 2.0 petrol Espace III. Apart from the problem I'm about to outline, the car is running well for its age.
When driving the car, all seems well until I stop when the tickover rises to around 1800 RPM. Once in motion again, the problem subsides.
BIZARRELY, when the car is stationary and over revving by itself, if I 'floor' the clutch, (without engaging a gear), the engine revs return to normal.
Sounds weird and impossible, but it is what I'm experiencing.
The management light is intermittent, and no 'fault code' shows up.

The engine has been replaced, but the problem happened before the new engine, and continues with it.

The idler control valve has been replaced, again with the problem before and after.

Any advice gratefully received!
Thanks.