It look like the right size. don't worry about the size. But please don't solder without testing the right side. Contact the pins, test the switch, if not work, turn the swith to the other side. Then solder it.
Hope to help this forum.

 

The second pic look like too big. The one is better.
But if you have a local radioshack you can try the one with 5mm.
http://www.radioshack.com/spst-12vdc...l#.VIvjXdzF-So

 

I went ahead and ordered the larger of the two sizes. I looked at the images erjon posted and measured and scaled them to the size of my Mini's panel. I came up with about 10mm as the approximate size. So I ordered the 12mm size instead of the 6mm size from ebay. I'll post up my results when I pull the panel.

 

switches arrived. I'll let you know if they're the right size in several days when I get a chance to work on the car.

 

As it turns out, the smaller size would have been the correct switch.

And....

My problem was not a problem with the switch itself, but with a plastic cover that activates the switch. It broke and slid out of position, and wasn't allowing the switch to be engaged.

I've glued the cover to strengthen it and will reinstall everything tomorrow.

 

Good for you. At least we have to useful information:
1) the switch size is around 6 cm.
2) it can be fixed easily.
Hope it will work for you. Probably you have try if it work before closing it, right?

 

6mm.

It looks like it can be fixed easily. I'll find out today if time allows.

Edit: Everything's working great now!

 

Nice to hear that you did fix this problem. Some $$$$ saved.

 

Well, it worked for about a year, but broke again recently--same symptoms; could only unlock the trunk using the keyfob.

Took it apart again and found that the plastic housing around the switch disintegrated and the switch itself broke apart. Now I have to replace the whole unit.

 

Pics ? Looks like you will need the whole handle. if its painted you can get the primed one and just pry the old outside off. If its chrome or anything else we have it.

https://www.northamericanmotoring.co...rking-diy.html