Hey CLD, welcome to the forum. If you are already renting and you are up to date with the rent then no problem. If you want to rent after you start the IVA then you may need a bigger deposit, a good reference from your last landlord and your IP and you may need a private landlord.
There are many landlords who would be happy to let their properties to people in IVAs, especially these days as there seem to be more properties available than are demanded. Viki gives sound advice, and this forum is littered with posters who have successfully rented once and IVA is in place. The trick is to be open and honest with the letting agency and take their advice.
I wasn't in an IVA when my tenancy began, but had been repo'd so I imagine the credit reference was already pretty dire for us.
We did fail the credit check, but as we had been upfront to the letting agents, they simply arranged for us to either pay more up front or have a gaurantor.
Once again I would like to urge caution when reting privately. You are far more protected if you rent from an agent - who will ensure that things such as your boiler are serviced and repaired. We had a problem with our loo and they sent someone out within hours to fix it for us.
I know all too well that private landlords don't always offer the same service.
I have had not so good landlords whilst renting but the one i have now is very good. Sometimes a bit over the top but if there are any problems he sorts it within hours. I think you can get a feel for how a private landlord will be when you initially meet them. Always make sure you have a contract through and read through it.