I have written to the seller advising that my view is that this is a Salvador Ysart weight. Having received extra images, I can confirm that one of the two millefiori canes definitely appears in several items attributed to Salvador Ysart, including at least two weights and an inkwell in my own collection.
There are also other reasons why I feel this is not a Paul Ysart weight.
However, at least one other Burns Sulphide (identical mould) weight, which has a garland of mixed canes, has in the past been attributed to Paul Ysart rather than Salvador.
One point that I made to the seller was that I was not aware of Paul Ysart using the same sulphide image in several weights (*) and yet I know of several other Robert Burns sulphide weights that use the same image mould.
(*) I should add here that Paul Ysart did use the same mould of a Basket of Flowers in a few weights but in those instances the sulphide was painted and it might be the case that there was a variation of colour for each example.