I don't know of anything in Zurich. There are a few pro catering/cooksware suppliers in Switzerland, but unfortunately of those that do have webpages that I was able to find, all but one were without prices. The one that
did have prices was certainly not competitive with Nisbets.
Nisbets also has French and German branches, the prices are comparable with the one in London. Unfortunately, they don't (can't?) ship to Switzerland (sigh,

what else is new....?), but if you can have them deliver your order to a colleague or friend in Germany or France it might be worth going that way.