Every time I go on the motorway I notice a problem with my tick over speed when coming to a stop.
Its either revving at around 1100-1200 rpm which makes the car sound like its revving really high, or its stuttering below the normal idle speed which makes my car shake horribly.

I do also notice the revs stick a little when changing from first to second gear.

The car has done 68k and was recently serviced just 2k miles ago at Awesome GTi in Manchester.
The Cam Belt has not been changed yet and I am fully aware that due to its age it does need doing.

Any ideas what this could be? I did think about changing the clutch switch as that might have been the revving issue between changing gears.