Thanks Gas Bags, that's good news. I'll give them a ring and clarify.
My take on the whole matter then is this: my Forms 465 and 540 are currently with CASA to issue a non-type rated B2 license. Following from that, if/when QAC have a B737NG OJT book approved by CASA, I can ship my journal to them for assessing and migration to the OJT book. If the work recorded in the journal equals 50% or more of the required OJT entries, the other 50% can be made up by POC and PCT. QAC then issues a Form 465 to add a type rating to my B2 license.
In other words, the whole thing CAN be done totally external to the employer (if one has rather deep pockets). Whether that's the exact path I'll follow or not will remain to be seen. But it's nice to get some clarity on how the system works (or should work).
Cheers