After a little experiment, I settled on sticking it on the film on the underside too. Worked great! Stuck strong. Easy to remove from MDF & aluminium. I used the Dial brand one from B&Q..

I tried the 2mm cutter on the settings above on some 2.2mm holes, and all seemed ok. I used a steeper angle helix this time and the chips certainly do fly like that!

I just did 1 pass.. am I right in thinking that due to this, the accuracy isn't great?
eg. some holes I can fit a 2.2mm drill bit in nicely.. others are too tight..
If I wanted it more accurate and repeatable, I'd have to pocket the holes at Ø2mm and then do a contour finish pass to enlarge to exactly 2.2mm?