Meditation bench - sore knees

[Fr****]

After I sit on a meditation bench (for an hour at a time) my knees are sore and achy - for a few mins. I heard that this is a sign my bench is too tall, so I have tried elevating the legs relative to the bench using a thick meditation mat and a blanket, but it hasn't helped. Has anyone got any advice please? Or is some mild-ish achyness normal after a 1hr sit? I don't want to cause permanent damage long term

[Si****]

Maybe this can help you as a Guide: https://www.theyoganomads.com/meditation-chair-bench/

[Fr****]

Thanks