TC RH750/450 replacement knobs.

[oldslapper]

It would appear that there is a long-standing issue with the knobs on the above amps. Most of mine have split and been glued back together. 
However, I’d like to replace them with new ones, but it’s been very difficult to source any so far.

The shaft is D shaped (see picture).

Anyone got any experience of replacing these, or any advice on what sort of knob would fit this type of shaft. I don’t care what they look like particularly, just need to fit.

Thanks for any help you can offer.

John 

[oldslapper]

As you were. Sorted…. Thanks.