Andy,
you will find IT DOES MATTER that he hasn't been given a contract of employment, the employer has a legal responsibility to provide one.
Best thing to do from day 1, is draft up paperwork, date them, both sign, ie: manual handling checklist, PPE, Health & Safety induction record/checklist, Employee safety training record (waterfed pole, working at height, ladders, PPE, displaying warning signs, slip, trips, falls) etc
Basically to show you have done everything you can to look after yourself, your employee and members of the public.
You all might say its over the top, but it needs to be done.