Ok, I think I got things working but ARS is a dog to get your heard around how it works.....
My understanding of it is that when off-noding calls, you need the 1st & 2nd dialling rules in the facility group so that the digits are off-loaded to the other side. As long as you have a rule that handles the node-local calls, it should route over an outgoing trunk (CO's in my case).
Also, i was tearing my hair out until i discovered that under Associated Extensions, Outgoing Access
must be switched to the ARS extension (82000 in my case). Despite setting up the correct routing groups, it took me a while to realise that outgoing access on each of the phones was pointing to a CO trunk group...
My next step is figuring out how to route calls when the full international code is dialled so that a selection of countries go over their own routing facility while not affecting the rest of the
I+ facility. Seems like some of my users have the full codes in their address books so this needs adding.
I wish there was a small app that was designed that you could load up with your routes and it would tell you where you call goes based on examples...