Fully synthetic or part synthetic?

[PaulSmith]

...

I am aware of the manufacturers recommendations. I am also aware of the quality of petrol that I use and the conditions that I (and most people on this forum) ride in and how they relate to the worst case conditions that the manufacturers recommendations must deal with. And I have a little knowledge of how oil works and what makes it break down. You yourself have mentioned two extremes of use, the 200k bike and a race/track day bike, and seem to accept that they require different treatment though I am not sure you knew why.

I did not suggest that you ignore the manufacturers recommendations, I suggested that you make an informed decision on the minimum oil quality you need based on your bikes usage, and for that, you have suggested that my bike is not well cared for.

So I ask again, do you know how to check the condition of the oil in your bike/car/bus/van or lawn mower so you can make an informed decision?
[Here is a hint, try googling 'oil blob tests'. They are not exactly difficult.]