If your IP becomes aware of this you might have to pay in the "lost" monies, probably by extending the IVA.
Mind you, four years ago PPI wasn't such a hot potato and it might not have been payable into the IVA (though I doubt it). However, asking for clarification will alert him to what has happened.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014
Did you fail to disclose a receipt of funds after your IVA had been approved? If so, this is probably a material irregularity which could cause your IVA to fail.
time to come clean to your IP and work with them to try and resolve this ...hoping they allow you to continue with your IVA....let us know what happens
Sharing from experiences of dealing with debt
There is a solution for everyone .... Just need to stay positive !
Your IP must have asked you at the end of each year whether you had received any additional funds during the year that you needed to declare? Did this happen, and assuming yes, how did you respond to that?