After enquiring about cowling packer plates from a couple of dealers without reply, I thought I'd make my own from some scrap 4mm ally plate. Stands me in an hour of my time, and I'm happy with it to be honest.
Yes mate, but I'm using a longer stroke crank, with a packer plate under the cylinder. It's only 3mm higher than normal, but combined with the porcupine head the cowling is a bit too far of the mag housing for my liking. I could probably fit the cowling without it, but don't want to stress the cowling, or mag housing threads.