Hi June,
Swiss Francs are the only currency accepted everywere in Switzerland. Nevertheless, you can pay with Euros in many shops, hotels, rail stations and gas stations etc. Many smaller shops, market stalls, kiosks, etc. only allow payment in Swiss francs.
Note that the Euro is a foreign currency in Switzerland, so if you pay with Euros, change will be in Swiss francs. For longer stays, it is cheaper and more convenient to have Swiss francs at hand.
There are just 2 people booked on this trip so far, both ladies. Your fellow traveller is also flying from Birmingham 🙂
Thanks,
Vickie