Thanks for the replies, I’ve changed absolutely nothing in my pedal/cleat or bike setup this year, but I have been running a lot more. Last week I had some extra holiday so I did 2 big hikes and 2 big rides, then running the other 3 days. This training schedule load is normal for me, apart from the hiking.
So, my conclusion from reading on the subject so far is that my knees/legs weren’t use to the long hikes and as a result I’ve upset the tendon. I’ve booked an appointment with the sports physio so hopefully they can check and confirm.
Half an hours ago I got kitted up, heading out for a 3hr ride, got about 100yards and turned back as already felt the knee! Frustrating when you’re used to training every day.