Found after, with my attempted chain adjusting, that I found/heared the chain intermittently clicking!!
So I assumed it was out of alignment. Therefore messed around with the cams until the clicking stopped, and it transpired that the difference in notches, between left and right, was back to its original setting (i.e. not the same ), be it, that both cams were now on a tighter setting of one notch, than originally set.