Puzzling.

I would think the crazing might actually be true crizzling, (age-related damage/deterioration). It wasn't a form decor used by the Ysarts.
I don't really associate those dark, stretched flecks with Strathearn (I might be wrong) and the odd base finish is more likely to be associated with Vasart than Strathearn, I would have thought. They were less organised (in terms of routines for production) and struggling to get hold of materials because of the very difficult circumstances (war) they were trying to keep operating under.
This did mean that base finishes sometimes accomodated what had been produced, rather than being consistent.
Sometimes a base might be too thin to add a blob of glass to, to cover the pontil mark, so it wouldn't be added, but they couldn't afford not to sell the piece.
My guts think Vasart.
Now I'm going to hide until somebody agrees, or puts me right.
