Thanks for pointing this thread out Gazza, I knocked one up at work from a sheet of 1.6mm alu. I'm not sure it will be up to the job though? I don't do a lot of metal work, so didn't appreciate just how soft it was. Still, it only took 30 mins to knock up, so I'll test fit it to the bike and if it's good I've got a sheet of 1.6mm stainless here, too.
Any opinions on if aluminium will be good enough? It's not got to take much impact, especially on a 750, it's just a guide.