As far as I can see there are no odyssey batteries that have the same dimensions as the Yuasa OEM battery. So if I got one, which I really want to do, it would need mods to the battery tray, or a new tray, in order to make it fit. Something I don't really have time to be mucking about with.
I think I'll just replace the OEM battery, I've found them for £50 including VAT but I'll give JHP a call and see what the score is.
Damn this!!!