Success! I have a fully functioning KR1AA, or very close to it. 
The popper has precisely no locator slots or anything to hold its position.
Tools
Cleaned up switch baseplate, you can see where the adhesive was and the outer copper washer sits.
The flexibility of the clingfilm disc to blank the sticky side of the tape is essential to getting a good bond without creasing IMO. Had to trim a bit for the washer to sit, it looks messy and was fiddly, but I just ran the tip of the little knife round it and peeled the excess.
Copper washer sitting clear on the outside.
And finally, if I could fit this with a NTG35 2700K I honestly would. Bloody e-switches!!! 
Many thanks to Hank for his refund or replace offer. I opted to wait before buying another, which freed this one up for either fixing or destroying in the process.