Nah! He was just playing.
There are no ‘right figures’ for Uchelwyr.
And we seem to have established that the one you want doesn’t, for the moment, exist.
I thought the discussion around exactly what you were looking for was quite interesting and useful. It made me go back to sources and check. (I may pop into the University Library and have a dig in some of their material). So for me; all bonus – thanks for the original question and thanks everyone for the lighthearted discussion.
I will keep looking for your figure Paskal, but as I said initially, I think DIY may be the answer.