This one was my fault. I had sent sample buttons from my spare bits bin to have castings made. Unfortunately, I had sold my Mark2 long ago, so I only had one Mark2 knob to send. Because my Mark2 was an older variety, it had the old pre-fix knob on it. That's why I had a spare knob - I put the knob fix in place, and this was left over. The cast prototypes all slipped as badly or worse than the original.

Stu now has a correct (fixed) Mark2 knob to make a casting from, but it caused a bit of a delay.