I have a TR executive which didn't come with this and was just wondering how simple it is to source one and install it? Any risks? Any help would be great.
Cheers

If you are near a wreckers that has a bit of a selection of magnas, should be easy to find. Maybe 1 in 4 have them at my local wreckers. Cost me about $2.

Installation is easy, unscrew and unclip the steering column cover to expose the ignition barrel for removal/fitting (single screw here), unscrew and remove the panel beneath (including screws in the change compartment) to get to the wiring to connect it up.

I had thought it was a simple case of plugging into an existing socket, but the socket on mine doesn't seem to supply power. I had previously jury-rigged "door open" power by squeezing wires into the footwell light. This could be a little dodgy if you don't do it right. A proper splice would be better, but I don't think any of the existing cable is removable for easy soldering. Test to see if the existing socket on yours gives power, otherwise you'll need to do some soldering and hijack power from elsewhere. There's probably better places to get power from, this was just the easiest I could think of at the time that was guaranteed to give me the power when I wanted it.