In certin situations i think your better off keeping under the threashold ,i know a girl who runs a small tea room in an office block ,she was wondering the same as you,as her raw material is mostly v.a.t exempt fruit,veg.bread,meat,milk,coffee,etc she stood to lose if she went over the threashold,as she would have had to charge v.a.t on hot sandwiches,coffees and hot food take out ,paninis ,breakfast rolls etc.at 13.5 % as her business is small it would have hit her for a good lot of vat with no v.a.t on invoices to claim back. depends on your situation !