Yes I know there's a guide for the GTV but the angle of the boot on the Spider makes it impossible to fit the badge with the boot lock in place so...
1 - Sort out your beer arrangements amongst yourselves..
2 - Open the boot
and remove the plastic cover from the catch
3 - Undo the 2 bolts holding the boot catch on
4 - Pull back the clip holding the connector arm to the catch release solenoid and detach the arm from the catch. The catch will now come away. Undo the electrical connector - try and leave the boot side of the wire hanging out or attach it to the boot with some tape so it doesn't disappear back into the bodywork
5 - Get hold of the big bit of plastic (circled in red) and rotate it clockwise away from the pin. The photo shows it after rotation. Its quite stiff.
6 - The piece of plastic can now be removed from the back of the lock. The the lock will come straight out.
7 - Now the lock is out its easy to remove the circlip and swap in your shiny new replacement badge.
Reverse all the above steps to refit i.e.
1 - fit lock back into boot lid
2 - put the big plastic retaining clip over the back of the badge and then rotate it anti-clockwise until it clips around the pin - I used a ratchet extension to leaver it back as I couldn't get enough leaverage by hand.
3 - Offer the catch back in and clip the solenoid arm back in place. Attach the electrical connector.
4 Bolt the catch back on and replace the plastic cover.
Not a scraped knuckle in sight!