I have also have had a strange clutch problem; big problems getting gears then damn near impossible. Turned out to be down to the chassis replacement that was done. If I remember correctly, there had been a change in the type of clutch over travel stop fitted from a stop mounted on the pedal box to an internal one in the clutch housing but when my chassis got changed they also changed the pedal box but not the over travel stop which meant that there was no end stop for the clutch which inevitably led to clutch failure and some red faces at the factory. It did all get sorted out really rather quickly. Please read the above with the words "VICE VERSA" in mind - I'm just back from watching the rugby in a local pub.
Perhaps more likely would be that the plastic socket/seat that the ball of the gear stick pivots in has started to fail/break up. When this happens the gear shift becomes very notchy and could if it goes further easily become obstructive. There is also a spring steel washer above the socket/seat that has three tangs on it that appears to be prone to failure - I don't know that this directly causes any symptoms but...
The good news is that if the gear stick seat is the problem it is very quick and easy to take it off and find out and just as quick to fit a new assembly. The bad news is that MMC appear to insist on a two month wait before sending out the replacement parts.
Good luck with it.
P.S. what track did you go to?
