You need to talk this through with your IVA company ASAP. You would normally be allowed up to 6 months salary equivalent from any redundancy payment, the remaining will need to be paid to your IP as a lump sum. Going forward from there really relies on whether you gain employment with in the time frame set out by your IP. But communication is your first priority.
Last Payment made 04/12/14. Completion Certificate 25/7/15. IVA company GT. No Issues
I agree with Merlin ... a chat with your IP is in order, sooner rather than later. If you do not secure alternative employment within a reasonable period you might need to agree a payment break with your IP, which will be added back on at the end of the IVA.
The way forward will also depend on how far you are into the IVA.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014 http://foggy.blogs.iva.co.uk