Whether you will have to advise your insurer will depend on the question they ask about driver’s convictions. Historically, insurers tended only to require speeding offences to be advised to them, if there were more than 2. Each insurer will have their own requirements, so it’s not possible to give a single yes or no answer.
If in doubt, check! You dont want your insurer "playing up" in tge event of you having to make a claim.
Just as a heads up, if you allow someone, who is not a named driver on your policy, to drive your car then they will only have minimal third party cover regardless of whether they have a fully comprehensive policy on their car.
In addition its only policy holders, not named drivers, who have cover for driving other cars AND if the policy holder is under 25 they almost certainly won't have "driving other vehicles cover" on their policy.
I dealt with a fair few cases where the above circumstances applied.
If you lend your car to someone who it turns out isn't insured (As it any of the above scenarios) YOU will also be prosecuted for permitting the offence of them driving without insurance.
It is incumbent on you to physically check their insurance covers them.
If driving someone else's car that car will require insurance in its own right, you cannot use "your" insurance to drive an uninsured car!
Car insurance can be a right nightmare at times!