Hi Julia welcome to the forum, I'm sorry I can't answer your question directly but if you stick around I'm sure a professional will be along very soon to advise.
I know there are other self-employed persons on the forum within an IVA too x
IVA final payment left the bank on the 26th January 2013...looking forward to a debt free future.
So long as your business is profitable, and does not rely on the taking unusual credit - apart from purchasing supplies on usual payment terms - the IVA ought not to affect it. Presumable the ongoing trading will be helping to produce funds to pay to creditors in any case.