TD5 revving on gear change !

Afternoon all , my manual TD5 disco has just started doing something strange !
When changing up a gear the point between gears ie when the clutch is pressed the revs hang as if I'm trailing the throttle with my foot , but I'm not , I have been exaggerating taking my foot off the throttle but it's still doing it !
Any ideas peeps ?

yes you need a clutch switch, provided it's not a wiring issue or accidentally unplugged, google out MSK500020 e.g http://www.lrdirect.com/MSK500020-Switch-Fuel-Shut-Off/ , it's near the fusebox on the clutch pipe, see attachments

Just what I wanted , a quick , concise answer
Thank you so much
Baz

Just to report back , I've changed the switch for a genuine LR one and no change !
What would be the next line if enquiry ?
Baz

Not a big expert on this area myself, but I believr that the TD5 throttle is a "drive by wire" system, having a potentiometer rather than a cable.

Could this be where the problem lies?