Melanie's advice re. holding onto some of the sale procedes as a deposit is wise, most landlords will be happy if you are offering good security. Failing that, if you have anyone who would be willing to act as guarantor, that also helps. We've rented for some time and moved whilst in the IVA. Have found that the best policy is honesty, and whilst it's a litle embarrassing, worth just stating the situation and seeing what they say. Agencies themselves don't seem to have too much of an issue with IVA's, those that do simply refer to the vendor to see whether they have any problem with the idea. So far we've never been declined, but then we do offer 3 months rent up front, and have rferences from previous landlords showing no missed payments over 15 years, and like you, can demonstrate that we never missed a single payment to anyone, for anything, prior to entering the IVA.
Good luck with the move if you decide to go ahead, hope selling isn't too much of a prob where you are.
Martin