Just some info.

I had the dreaded sticking ignition key problem on this thing. Most places would seem to suggest that replacing the lock barrel is a must to fix this one.

Anyhow, I popped the lock barrel and inspected it. The barrel itself is cast in aluminium and as usual with such, wear had caused particles of aluminium to contaminate its grease (this explains why this problem is known to usually start manifesting itself in hot weather). I cleaned the thing up, regreased and replaced it and all seems fine. If anyone gets the same problem, this is worth a punt as getting a new barrel made to match your keys isn't cheap.

Incidently, while the manual says to remove the steering wheel to do the job, with the benefit of hindsight I do not think this is necessary. The two screws at the front of the column shroud holding the two halves together can be accessed by turning the wheel and the shroud may be removed with the wheel in place (I had actually done this before removing the wheel). After that it's just a matter of unclipping the wiper stalk to provide access to the barrel release.