Hi Jimbo, welcome to Switzerland, and to the English Forum.
I'm old and not in Zürich, but I can tell you that there is an ongoing social "event" in Zürich with a strong likelyhood of meeting other English speaking folk of many ages and interests is to meet up at the Viadukt Market on Thursday evenings. The British Cheese Centre is run (owned / operated) by a very friendly member of the forum and near as I can tell, there are plenty of other folks who head there weekly.
It's not all cheese of course, apparently "chaps and chicks" are involved as well, but the cheese is really something too! (I believe there is also beer to be had, either there or from a neighboring vendor in the market)