Bertrand, he started Reception this year and I've checked him every week since, it's just this week we found the horrible little buggers! DS2 has proper ringlets but luckily he loves having his hair combed, so hopefully he'll let me delouse him later
If he hasn't got a lot of hair then conditioner and a really thorough nit comb every 3 days for a fortnight should do it - won't take that long. But yes Hedrin acts physically rather than chemically/biologically so should be safe.
Nit comb at every meal worked for us. dip in boiling water to fry the fuckers, wipe off and continue. Easiest ones ever to get rid of. Don't forget to wash, freeze or isolate the millions of other things that go on his head like the car seat and pram.