Thanks for the replies. I am aware of the wheel bearing issues. I have been caught previously. I have since changed them twice, the ones in the bike are new. This is not the problem.
The roads I was riding are windy mountain roads, I don't recall them having a lot of crown on them. Maybe they did.
I have done over 20,000 kms on this bike and its something I've always been aware of, I have not done five days of continuos riding on it before so maybe I had too much time to think about it.
It's possible I done just wind it on a bit more on right handers.
I'm a lefty by the way.