Thank you, I do have a spare foot, so could try sanding that down, or I was thinking of trying some clear nail varnish or possibly gluing some suede to the foot, I can always take it off if it doesn't work. Failing that I may try masking tape down each side of the stitching line, so the foot can dig into that and not the leather! I do like using it so it would be a shame to give up on it.
Thanks for that, the tubing sounds a good idea, or possibly a little bit of cork.