I got a reply back from Support; I want to keep this thread updated until the issue is solved, just in case anyone else has similar problems, and finds this thread.
"Unfortunately we are currently not able to print your model due to previous experiences, 9 out of 10 models break during the shipment, leaving a lot of unhappy customers as they will have to ask for a reprint, which will take time.
This is mostly because of the connection between the tail and the body."
What I take from this is that I'll have to fix the model myself with the suggestions they've suggested (hollowing out the tail and making the tail to body connection thicker), until Shapeways implements the "Printed Flags" system. Annoying, but doable, it's just a shame, as I know the model I have is incredibly sturdy.
I further stress tested it last night by holding it by the tail only and waving it around (I would not dare suggest this to any customers buying the models), and I'm confident that it would work. Nevertheless, I'll spend today making the necessary alterations.