Hi Mel
mm, yes I debated over whether it was a one, but figured it was a 7 without the cross across it which is how I would imagine it might be if Continental. My grandma wrote like this as well (English lol), but you could be right.
No, it wouldn't make a difference to the year if that digit were a 1 though (if it were English rd numbers).
I wonder if anyone else recognises the opalescent pattern. Harrach did do versions of as well. I don't know about any other continental maker so can't add any more.
m