Can a person who has passed their car driving test within the last two years act as an accompanying driver?

Yes, as long as they have their full licence with them.
Yes, as long as they have completed their Essential Driver Training (EDT).
No, unless they are a qualified approved driving instructor (ADI).
No, they must hold the full driving licence for a minimum of 2 years.

Explantion: To be an accompanying driver for a learner driver, you must have a full driving licence for at least 2 years.

Safe and Responsible Driving