Hi emmac and welcome to the forum
Speak to your IP about this as soon as possible. Everyone can make a mistake once - especially if you have had additional unforseen expenditure to cope with over the last year - and if so make sure you make your IP aware of this producing receipts if possible.
But you must be prepared for them to monitor you more closely in the future. I insist that clients submit their wage-slips to me on a quarterly basis, so that we can collect the money throughout the year, and some clients even pay it over monthly to avoid spending it.
Remember an IVA needs a degree of self-discipline on your part to work towards that successful outcome of being debt free.
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