i my self had this problem, in december 2009 i went vat registered.
i took the hit on some and others i charged went on the fkat rate wgich is 10.5% and that is discounted for first year by to 9.5%.
You know your customers and who you will get away with increasing, i ended up even which is were i wanted to be, since then though iv had plenty of new work which has incresed me to way above vat and i even make a little out of charging vat.
Going vat registered is all part of expanding and growing from a one man band, if you have any ambitions to becoma a resonable side you will have to start to pay sooner or later.