Thanks Bijingo,

I considered both of these, although unfortunately didn't have time to do a full knee assessment and some accessory movements obviously would have helped. (I did test patella compression when doing something else though, and that elicited no pain at all).

The question I'm asking myself, is if it were either bursitis or OA, why would direct palpation only cause pain when the knee was extended?

The superior translation of the patella in flexion is doing something but my brain is too muddled to get the connection, which is probably obvious. Though maybe I should be paying more attention to the functional (weightbearing) movements which are problematic?

And PS- no crepitus.