Ok, after Dereks question i decided to get a couple of photo's quickly of the selector mechanism.
Here is a close up of the kickdown mech on the left and the selector on the right with the valve block removed, you can see the spring on the right that gives the notchy feel of the selector
This is the selctor mech close up with the top half removed (just lifts off)
And here is the kickdown mech close up, not a great deal to it here. on the right you can see the pivot for the top half of the selector mechanism
Here is the underside of the valve block, the valve with the long plastic link (top) is not spring loaded and is the selector valve, the heavy duty one below it with the roller on the end is the kickdown valve and is spring loaded to return the cable i presume
Sorry about the large pics but i thought it best to post them as large as possible for clarity.
In my opinion the gearbox is built to a very, very high standard. it is one of the best bits of engineering i have seen in a long time. I cant explain it but everything (look at the selector mech) is very highly engineered no matter how little stress it is under.
D