Axminster sell the self-adhesive sandpaper in 600, 1250, and 2500 grit only. Is the 600 course enough and is the 2500 fine enough or did you get other ones elsewhere?
600 and 1250 IIRC, I use them to hone the edges, just a few strokes is enough. Over sharpening and getting the angle slightly wrong - i.e. blunting - is my biggest bugbear.
Re the self adhesive, it is convenient to just slap them onto a piece of mdf off cut, or a bit of 2x3.
Blup