Hello. I have a friend with a large amount of antique furniture , silver and artwork she would like to have appraised with intention to sell it. Does anyone have a recommendation of a reputable company doing this in Zurich please?

Problem with antiques is they are out of fashion at the moment. But, how much is your friend budgeting for the appraiser?

http://www.rudolf-bosch.ch/en/expertise.html
I don't have personal experience; have just walked past their shop in Kirchgasse, Zurich.