Hi Rory, just let me know when you have something ready for a proper ol' test and I'll be more than happy to have a good play of it. From what I've heard, ipad 3 safari is quite fast when it comes to html5 games (I get a steady 60fps on the game I'm currently designing, but I'm keeping the effects etc down to a minimum) so it's probably worth getting a few folk with older devices to have a test as well.
There's so few Construct 2 iOS games (only about three or so in the apps store that I can think of offhand), so its good to see someone else making progress with one.
Best of luck with the game, and thanks for entertaining me so much with the Unicorn game (which is actually partly responsible for me buying a Construct 2 license in the first place. The humour won me over).