I have an old Canon Winchester andc 3 of the knobs are beyond repair
(I've bodged it a few times over the years when they broke off) its a
bit of and old cooker but does anyone have any idea where I might be
able to buy some ?

The best I can describe the shape of the fitting is like the shape of
the letter D.

I'll go and google a bit but in the mean time any advice from here would
be good.

Cheers fellas.