Eye30, where's the fun in taking a shortcut?
Tim, I managed to get it out thanks! It turned into a voyage of discovery, eventually I found the culprit.
I first removed the two screws on the housing that point upwards to the roof, and then gave the cowling a good tug. No game - it wouldn't budge. So I thought it might have something to do with the lower cover beneath the steering column. Fast forward an hour and I had the panel near the fusebox off as well as the bottom most cover beneath the steering column, and I also discovered the tracking unit left behind from the previous owner. I ripped that out and saved about half a pound of weight. Woohoo, hypermiling here we come!
At this stage I still couldn't figure out how to get the cowling off, so I decided to use a bit of violence and gave it a hefty tug. I heard a pop and the cowling gave way, but at the same time I heard something break off and my heart sank, thinking that I broke my dash. It turns out it was only a clip that was dislodged. Another thing I discovered was a little fan near a grille in the dash next to the climate controls. My guess would be a probe to control the temperature inside the car.
The speedometer 'glass' has four protruding nipples that are secured inside the cowling itself, so I wrapped some insulation tape over the nubs and cut and fitted some old motorcycle tube inside the recesses in the cowling, hopefully stopping the rattle which I will find out tomorrow when I leave to go back home.
I took a few pictures but I'll post them up on Sunday or so, as I only have dialup speeds on the farm currently