No, not the Jeremys Paxman or Clarkson, but these:
They can be had with 4mm or 6mm shafts suiting both the 4mm shaft of the 2 pole 6 way Elma switch I got from HiFi collective I’m using, along with the 6mm shaft of the Vishay 50k logarithmic rotary potentiometer I got from Farnell.
Here’s the amplifier with the dimple knobs in situ:
I bought these from 4most electronics, who have a stock now of 19 of each of the 6mm and 4mm dimple and dome type. Their website is bit out-of-date, but they are the main distributor for Elma (including audio quality switches) in the UK. Haydn has been very helpful to me, so I recommend you contact him directly.
This might sound like a bit of paid advertising, but it’s unpaid; one of the hardest things I’ve ever found about DIY HiFi is finding hardware that looks as good as the circuitry sounds. And finally, I think I’ve achieved it thanks to their kind help!