Defintely one of the thousands of regular production Strathearn closepack weights, made from 1964 to 1980.
I can see why somebody could think the base is "like early Vasart" as it seems to have some basic grinding. However, the grinding (if that is what it is) is not consistent with the usual early Vasart style as it appears to radiate outwards all around the central pontil mark. And the pontil mark seems to be fire-polished, which is something that was quite typical for Strathearn weights but, as far as I know, was not done for "early Vasart" items.
Vasart (both early and later) and Strathearn domes came in a whole variety of sizes, from quite low to surprisingly high.