I'm curious: Could you not simply designate the new hire a 'contractor' since they are working from their own premises? You could then save having to deal with all the employee paperwork and insurance...?
You have to be pretty careful with this sort of thing. You can't just say someone is a contractor and they become so. This is covered by something called 'IR35'. What this basically says, is if someone looks like an employee, they're doing the job of an employee, then they are an employee, whether you like it or not. Most UK IT contractors will be pretty familiar with this situation, and the ways to avoid being caugh…
IR35 was introduced to stop contractors from setting up a limited company and then having the company contracted instead of the individual. The individual would then take dividends out from the company, which are taxed at a lower rate and not subject to national insurance.