I agree, running the fluoro from the mains bypassing the transformer is way too go.
I can help you with that.
New fluoro ballast and tombstones as suggested , will illiminate possible fault or future fault, as the existing euro ballast is a bit sus, and slightly under rated at 220v.
Since the price of these parts is so small.
Adam, i pretty sure , you are well on the way to making this x files a reliable machine again.
Let me know when you new transformer arrives, i can help fit and mod the fluoro. My knowledge of dmds is limited, but growing.
I find my solid states , less complicated.
Remember when i problem occurs. Rather, than replace the faulty device and reconnect. Think why did it fail, is there another fault that has caused this. Inspect and test. Slowly slowly. If you are not sure. We all love a quick fix. These come from experience not luck.