I have to admit some times simple faults are hard to find, I remember a Morris Minor car, using far too much fuel, we tried everything, could not work out why, so asked the old lady to take us for a run so we could see if anything she was doing, she pulled out the choke and hung her hand bag on it, she thought that was what it was for.
But pilot flame, how could any repair man fail to light the pilot? In fact how could the user fail to light pilot flame, some thing does not sound right, maybe pilot flame would not stay lit, fault with flame out sensor, but should not be even calling a repair man for that fault.
Some thing missing there?