Your budget looks very frugal to me. Are you sure that continuing with the IVA is the best way forward for you? I would expect to see you spending at least £200 per month on housekeeping, and there is nothing in this budget for contingencies, medical expenditure, insurance.
I suppose things might ease a bit when your car finance agreement concludes, but I would seriously look at the other options of DMP or bankruptcy - even though you are self-employed most people are still allowed to continue trading whilst bankrupt.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
For further details contact me at
http://www.melaniegiles.com and view my IVA blog at:
http://melaniegiles.blogs.iva.co.uk