Art Glass by Patrick Stern

This is a piece I forgot I had!! Bought about 10ish years ago.
It's a small pot/ vase by Patrick Stern , a London glass maker,
It stands 4 1/2"h x 2 1/2 w & has square corners but rounded between.
It's very heavy for the size & an awesome blue colour!!
The side has an impressed bunch of blueberries or grapes & the base is stamped with an impressed shell pattern and signed Patrick Stern.
I don't know much about Patrick except he also has a brother who is in the art glass business called Anthony Stern ..
Any info would be cool :-)
Thanks for looking ....