On successful completion of an IVA you should find that you are able to get credit again, but this it may take a year or two for your application for credit to be accepted as information is likely to remain on the credit reference databases for around a year.
A successful completion of an IVA shows lenders that you are capable of managing your money. However, given that you built up large debts prior to the IVA it may be wise to avoid any kind of credit for a while.
Under the terms of the IVA you are required not to obtain any further credit during the period of the IVA - Individual Voluntary Agreement.