Pes Anserine Bursitis.
Presents a bit like medial meniscus tear. But good physio can differentiate, even if they have to go back to text books.
Frustrating as this is the good knee. RICE is the treatment. Not easy to do with a crazy busy project going on at work. :/
Mostly ok now. Just think I was overdoing it by training every day. Still niggles a little bit though.