Hello
yes, you need to have a safety assessment completed by a specialist - I use cosmetic safety assessments by a man called Scott. He is very good and also very helpful.
you also need insurance if you are selling to the public - I W Walker are the craft insurers I use.
A safety assessment can set you back in the upwards region of £75 per recipe and the insurance (if I remember right?) was about £100 per year.
most craft fair organisers will not allow soap makers to hold a stall without proof of insurance too.
oh, and all of your soaps etc have to be labelled using the correct terminology and any fragrances need allergen declerations. and an open pot symbol to show use by once open date, address of maker etc etc (labelling drives me nuts lol!!)