Hi Jd. As you are, hopefully, aware the bonus is captured by the terms of your IVA and 50% of it is payable to the creditors in any case. Of course you can offer the remaining 50% as a full and final offer, and it this amount is close to the figure you have left to pay it should be seriously considered.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014