nikkib, I am struggling to see how you would need to pay £534 per month over 5 years.
That would mean that you were paying £(534 x 12 x 5) £32054 over the course of the IVA. Which means that in effect the only thing the IVA would do is freeze the interest on your debt. Debt management plans can do that without the repurcussions of an IVA.
Usually, IVAs are calculated on a pence per pound figure, but also use affordability. Often the minimum is around 25-40 pence in the pound. So a debt of £30000 in an IVA might be about £(30000x0.4/5/12) £200 per month.
If they are saying £534, then you probably have quite a high income on paper? What you would need to do is produce a 'statement of affairs', detailing all your income, and all your necessary expenditure.
IVAs are only more expensive than bankruptcy because they have a tighter description of necessary.
If you do go down the bankruptcy route, the procedure will be similar, in that you will still provide a SoA, but payments would only be for 3 years, if indeed you need to pay.
With no assets, you don't have anything to lose in BR, but it will make credit difficult to obtain.