Short answer: Do not rely on a headline saying the owner’s no-claims discount is protected. Check which insurer handles each type of claim, any recovery between insurers and what both policies require the owner to disclose.
Named-driver route
If the learner is added to the owner’s annual policy, a learner claim will normally be handled under that policy and can affect claims history and renewal, subject to its no-claims rules and any protection purchased.
Separate-cover route
Some separate learner policies state that a claim is handled away from the owner’s annual policy. The exact protection, exceptions and notification duties are found in the documents, not the slogan alone.
Ask precise questions
Ask about fault and non-fault claims, damage to the practice car, third-party damage, notification to the annual insurer, renewal disclosure and whether the owner pays any excess.