Sorry if i missed something, but is that a 4 speed type 9? That might be the issue, I have not seen one myself but I think they are shorter, might be easier to change the box for a 5 speed rather than do any other mods?

I'm pretty sure it was when I drove the sierra home, unless the tool fairys have stolen the top gear as well as hidden all my tools.

I had a sit in the car this evening and have decided to buy a remote lever as 1st is a little far forwards for my short arms.