This is an unfortunate problem for people who share a car, as most policies insist on a single policy holder and named drivers. However, some insurance policies do offer no-claims bonus for named drivers as well as the policy holder, so we would start by discussing this with your current insurer to see if this is something they can assist with. If not, it may be worth seeking out one that does, although generally speaking this acquired bonus only is only applied with that insurer.

Alternatively you can do as you suggest and switch each year between policy holder and named driver. It would be worth checking with your insurer how long a no-claims bonus remains valid without being a policy holder, as this can vary between companies.