hello Rose - welcome back - not heard from you for a while:)
regret I can't make out much of your 'mark' either - but if it's what I think it is, then it looks vaguely swan shaped, or perhaps upper case Z ?? - there are many surface irregularities on glass which get interpreted as marks, unfortunately.
As for the decoration, this looks to be in the form of metallic lines which appear to be painted onto the glass - am sure I've seen this previously on early to mid C20 glass - probably pieces of a more decorative nature than utility items.
this looks attractive though
