Don't you think it'd be better to start a new thread seeing as that's on a different subject?
BTW I'm currently using the same medium as what you're talking about. I think you're on about the Organic Composted Bark you get in 20 litre bags. I've repotted recently using this and John Innes cutting compost (or summat) mixed together 50/50and I'm having no problems so far. It's got good airation so you shouldn't have to add that much perlite.
Hope this helps you out.
Peace
