Thank you David – this is all really helpful. I didn’t know where to start before but this has given me some good pointers.

The knee pain on stairs is very relevant to me. I think there’s something awkward about the way that I move. I think my femurs rotate inwards which is why I think the pistol squats and glute bridges cause me problems.

Re the orthotics, I have very high arches. I tried running shoes for pronation and they helped initially. I definitely have weak glutes and hips too but I thought I would have seen an improvement after doing the strengthening exercises for over a month. Anyway, thanks again and I’ll see how I get on with all this.