Although the Tornado gearbox has been bullet proof, the same can not be said of the selector mechanism. There have been a couple of reports of it not allowing any selection at all.
The problems I am aware of are:-
1. The pin that centralises the return spring has worked loose & fallen out.
(easy to fix - deform the pin & tap it back in place)
2. Broken return spring - which has just happened to me, at 43,000km.
Fortunately, I had the wire from an old mattress lying around that just about fit the bill. The spring constant was a bit lower, but, when bent into the required shape, seemed to work ok. I've ordered another, just in case.
A drawing of the spring follows, just in case anyone else needs it.