This is getting a wee bit complicated but I don't think the VAT disincentive is that big - and is certainly not one of the first handful of issues I'd have suggested you think about. And you can, after all, DIY the VAT - IMHO it'd easy compared with some of the jobs you do.
ISTM to ought first to consider, if you have not already:
a. would he be your employee? If so PAYE & NICs involves rather more than VAT - but they are equally not a showstopper since you are patently able to use a PC and these days you can do it online. Of course there's also employer's liability insurance, working time directive, grievance procedures.... b. would he be your partner? If so, I'd recommend heading for paid-for advice: you have too much invested in your business to risk it on a badly drafted partnership agreement; c. would he be your sub-contractor? If so, are you clear about how to set it up so he does not end up as an employee? And about the way you get your vigorish on the jobs you pass to him? And stop (discourage?) him from stealing your trade?
In short, there are IMHO bloody great barriers to anyone who wants to go beyond the one-person-band; but there are also a lot of people who try to help them do so, and we need them to do so now more than ever. So you might start by seeing if your local Business Link advisor or the like can give you a free hour. They might also be able to point you to part-time bookkeepers willing to do the VAT, PAYE etc cheaply if you don't fancy throwing £1,000+ a year at an accountant. After all, there are quite a lot of ex-HMRC staff in your area.