Motor car insurance, 2 cars & 2 learner drivers

Can anyone advise - I have just bought a car and am considering keeping the previous car as a second car mainly for my wife and kids to learn to drive with.
What is the best way to get insurance for this situation, ie myself with full no claims bonus, my wife who has been the named driver for 25 years and now my daughter (24) with prov. licence and my son (23) with prov.licence. Main car is 1.8 diesel other car is 1.3 petrol
Is it better to insure under my name with the others as named drivers, or insure each car separately or.........?

not if you are not the main driver of the vehicle. And you can't legitimately be the main driver of two cars. Your best option is to insure the 2nd car in your wifes name and they will most likely allow her a full introductory no claims bonus for her driving experience depending on the insurer.

They will rate the policy on the most rateable driver so you will pay as if it were your son being the main driver but your wifes potential NCB will bring it down.