Can anyone help me with tips for fitting the white third brake light on a Cooper with Chili pack spoiler?

I have the new red/white rear lamps and the kit comes with the white third brake lamp which I'd like to fit now I have the main lamps fitted.

Had a quick go yesterday and it looks more or less impossible without removing the spoiler...

Actually, I tried unbolting a corner of the spoiler but it still wouldn't budge - is it bonded too? I can only see two bolts holding it on in the far corners.

Anyone done this relatively simply, or is it a bodyshop job?

It is a TIGHT FIT
Undo the mountings yo have found
Get a second person to help.
One person pushes up on spoiler whilst the other removes/refits the lamp

I have a recent Cooper and i believe they changed the way the spoiler is attached using a far stronger adhesive and only two bolts meaning that there is a lot less flex in the spoiler. I had an absolute nightmare fitting my white brake light as the spoiler just wouldnt budge. In the end I covered the whole area with white grease, smashed the old redlight to get it out (only way it was coming out!) and then had to squeeze the white one in, again not easy - patience, the right angle of entry and force is what you will need. Good luck!!