Ok sounds great... I ordered a new one from carolyncbishop above which is
http://www.bimmernav.com
It was around $500 with comfort access & a new blade or $430 without. Much better than the $1200 I was quoted at Artarmon BMW.
I found some cheaper sites in the US for around $250 but you need to go in store.
There is also a place in the US that re-flashes used keys, presumably from wreckers for around $100 but of course they don't have Australian Freq keys.
Anyway keen to hear if you know how to re-code comfort access. I understand the key part is easy but instructions would be useful.