You can go down that route, but I would bear in mind the age of the MX5. You could insure it on a classic car policy (that does not use your no claims) and have as a second car, then use your no claims on the new car you buy. I'm not a fan of multi-car policies, as you can affect your no claims history across the full range of cars you have access too. If you feel you want the convenience of one, Admiral's multi-car policy would suit, but you will find many insurers offer them. Aviva is another one that it may well be worth ringing.