Don't despair Mum! Finally the solution is here.
I took my daughter to see Shayne at the Head Lice Clinic, because the treatments were not working and she kept bringing them home from school.
Shayne makes his own treatment that leaves the hair soft and lovely (though not smelling the greatest), he is very thorough and makes sure he gets rid of every single egg.
Highly recommended! A little pricey if the hair is long, but you get what you pay for.

Approximate cost: $82