Hi Lokami,
You can get a very low commissions if you open a proper trading account with an online broker. I opened one recently with "Interactive Broker" (Google to find them). Commissions for < 10000 USD are about 0.01% (compared with 2-3% at a high-street bank).
It's usually pretty easy to transfer money into the account (by wire) in GBP and then to withdraw the same amount (again by wire) into your Swiss bank account in CHF. Although this isn't the intended purpose for such an account, you can use it to for this.
You will need to take a little while to setup the account (all online) and to scan passport and other docs for the opening. But once you've done that, it's really easy.
As for the "rate", well that's anyone's guess!
Alex.