Brilliant ! I am sure you are spot on! The glasses look familiar to me, Ive seen Siddys exhibitions and much of her work,
Ive got a couple of pieces, the writing, and size is the same.
I will drop her a line, i hope she wont be upset that something maybe she made for a gift, ended up in a Charity shop !
and my sincere condolences for your sad loss, the Swan was beautiful,