You can drive your car on foreign plates/insurance for one year after entering the country. Then you have to either register it here, or permanently remove it out of the country. I don't think you actually need a Swiss insurance for that period.

Your UK insurance should be absolutely sufficient. The insurer has no means to know whether you live abroad permanently or were out on a holiday trip. Unless your insurance rules state clearly that insurance is ineffective for prolonged stays abroad, you have no reasons to worry. The civil responsibility insurance will be effective anywhere in Europe, including Switzerland.
You might want to buy an European "assistance" package though. This is in case you wreck your car and need it transported back to the UK for insurance claims.