Hi raffles - welcome to the forum. You can pay off an IVA early. Your credit rating will still be affected for the 6 years however from the time the IVA was approved.
You could offer a lump sum as a full and final but offer as near to the original promised dividend as possible. Of course it will depend on circumstances and where the money would be coming from but lots of forum members have completed IVAs early.
Agree with ginger - you normally need extenuating circumstances such as redundancy or illness to do a full and final.
Where would the figure be coming from?
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk