Unlike some microlight insurers that will insure the pilot to fly any microlight, most GA ones will only insure the aircraft.
This wasn't my experience insuring my own aircraft. Named pilots versus any pilot with my permission made very little (can't remember how much) to the cost of the policy. Adding the restriction that they were at least as experienced as I am reduced the premium a bit and that one I did go for because it didn't seem very restrictive as I am not likely to be lending it to anyone less experienced.