I don't know if this will help you, but I had a credit card that I didn't include in the IVA as I hoped to cling onto it for dire emergencies (no car, lose job etc). I was asked whether I had any credit when I entered the IVA, I said yes and this was never followed up so I thought it was allowed. (duh, I know).
However, they backchecked and when they saw I was in an IVA they closed it with a £500 balance on it (about 2 years into the IVA). I was having my yearly review and I filled it in and stuck a note to the back explaining what had happened and saying that they had agreed to accept £50 per month, which I would have to include in my I&E statement.
This was accepted and I made all of the payments until it was paid off - however I was right in the middle of a Debtmatters/GT handover, and I think DM just agreed to it as they weren't particularly bothered anymore and so GT could see it had been agreed in future years.
It has to be worth speaking to your IP about it because they are there to help you and to get the best result for your creditors, and forcing you into bankrupcy probably isn't it.
They might be able to include the debt to your current IVA (I've heard of things being added while in IVAs) and/or they might suggest an extension so that you can get it all paid off.
Seriously though, speak to them. Be honest and frank and you'll feel a hell of a lot better for sharing it with someone who can help you get on the road to getting it sorted.
Good Luck
