Paul,
When an older person registers himself as the main driver on a policy and uses his no claims discount to bring down the premiums alongside a new driver, then it is called
car insurance fronting if the new driver uses the car more often than the main driver. The whole point of being the policyholder is that you will use the car regularly and any named drivers will use the car occasionally. Fronting usually happens with
young new drivers to bring insurance quotes down.
In your case, I don't think fronting is going to be an issue but just keep in mind that you shouldn't be using more often than the main driver (as in taking the car to work) otherwise the insurance company might invalidate your claim on grounds that you should have been listed as the policyholder.