My apologies for the cynicism regarding private part marking, I was probably harking back to the days when RS/Radiospares only had their stock number printed on parts and refused to tell you who the manufacturer was or even reveal what the industry part number was (unless you asked the rep nicely!).
After spending most of my career in designing industrial electronic equipment where you would be sent back to the drawing board and told to do better if you presented a design which could not tolerate the parameter spread of the chosen devices, it is not easy to appreciate the different domestic design criteria...
Maarten, I have attached a picture of the 0N transistor for you. Definately a TI Bedford UK produced device, to me the first character looks more like the number zero rather than the letter O.
Adrian.