Can´t offer any info specifically about a UK registered ski company operating in Switzerland but here are some links to important info you should be aware of concerning the activity of ski instructor and requirements/legislation in Switzerland:

• Reglement sur les maitres de sports de neige, les guides de montagnes, les accompagnateurs en montagne, les ecoles et les entreprises proposant ces activites (French)
• Swiss Snowsports (French or German)

In Vaud, you could contact the Police Cantonale du Commerce to get info.

Good luck!