Thanks madisongrrl & MrsD
I've calmed down a little now and am trying to think laterally to come up with alternative tactics.
I would love to see a functional medicine doctor - however I don't think they even exist under our medical system. Same goes for independent/private lab tests. They probably are in the larger cities but I'm in a small rural town. Thanks for reminding me about co-factors - it had crossed my mind about getting tested for other possible deficiencies but B12 seemed the most likely and I had the earlier tests as a base to go by. Will keep it in mind.

For me it was interesting to see that my B12 had risen slightly between Jan and April - what I hadn't told my GP was that I had started eating liver pate about 3 weeks earlier as I knew that was a concentrated source of B12 - so maybe I am still absorbing some - just not enough.

MrsD the aafp article is excellent and I had taken just the diagnostic diagram to my GP but when I tried to show it to her she got that glazed look and dismissed it. You can lead a horse to water but ...
Thanks also for the link to Dr Snow's article - I had seen it earlier but forgot to bookmark it.
As an interesting connection - researching further this morning - I think the Schilling test may still be available here in NZ - so maybe - just maybe - there is one advantage to living in a country with a somewhat redundant medical system.
Thanks for the encouragement - it's helped me continue after a rough weekend.