Hey s-n, welcome to the forum. In an IVA you would have to list ALL your outgoings so the insolvency practitioner can see how much you have left for the IVA payment. You would have to stick to a budget and it's different for everyone.
I think the general thing is that you can live comfortably whilst in an IVA. you have allowances for things but in general you dont have spare cash, other than contingency money and money you save from your other allowances if your one of the lucky ones who can do that.
Two of us in our IVA and we have £150 a week for food, petrol and ad-hoc spends - sounds a lot but we have two cars that take £80 a week in petrol, food between £50 and £60 and what's left we treat ourselves to a bottle of wine or two ! It is a struggle but worthwhile and rewarding !!!!
Sharing from experiences of dealing with debt
There is a solution for everyone .... Just need to stay positive !