The 5K refers to the likely 5 thousand pounds sterling or 7.5 thousand euro you will pay for your instructor rating tuition.
My comment was referring to the pre-requisite flight check per the JAR requirements to ascertain suitability for training as a flight instructor.
The question arises as to the value to anyone other than the school hiring the plane for the check, or the person being paid to do the check, of this check. How many people are considered unsuitable to become instructors as a result of this check? If the school is also doing the checking, are they truly likely to say no when the possibility of a 5000 stg piece of training business is on offer to them? That would be a bit like turkeys voting for Christmas.