Making Scented Candles

Hi everyone I really hope you can help. My friend and I have been making our own candles and have been thinking of selling them. Someone has told us that you cant make and sell scented candles without having appropriate certificates whereas its fine with unscented ones. She seemed to think it was some sort of food or hygeine certificate for using essential oils?! is this the case, many thanks in advance

 

ooh i think i have found a link with the answer regarding CLP which explains it all