I think the cam was always on the way out because I've not done the mileage to ruin it. It also explains the tappety noise I used to hear when I first drove it. It also explains why it drove okay but not ever 100%.
Another silly thing is the pratty chrome dip-stick....you cant see the level when it's fresh oil

So after all this, the thread stays true to it's title...basically, I need a new cam!
Can you swap the cam with the motor in? It looks to me like you'd remove the rad, pump , timing cover and some of the front panel and slide it out the front.....correct?
At least it drives (badly) now