Thanks for getting back to me, really appreciated; as gmorph says, I think you might just be the only person out there who's done this!
Just to confirm, before I order one of these units; you uploaded APMrover2-v3, set GPS_TYPE to 9, plugged in the Zubax and it worked? Sounds too good to be true, but that's fantastic news if that's correct. I've spent two days this week trying to get a NMEA feed working!
Also, does mission planner display HDOP, number of satalites etc, just as the standard pixhawk GPS module?
Thanks again, Russ