I bought Full Marks solution and a Lice Breaker comb after reading about them here and they worked
I always recommend both. They do work.
Lice Breaker comb is brilliant. I only ever use that and cheap conditioner on my kids. Most time it only takes on session to get all the nits/eggs out. But I do follow up treatments just to be sure.
Make sure you are doing follow up treatments within 7 days of the initial treatment to catch anything that may have hatched/been missed.
Treat everyone in the family at the same time. I have had nits as have my non-school age kids and we have not been scratching. Often we just have 1 adult which you never see just be looking.