Well done on completing your iva. The iva will come off your file on the 6th anniversary of its start date - in theory you need do nothing but in reality if it doesn't drop off with a few weeks of this date I would send a copy of the completion certificate to the insolvency service and the credit agencies asking them to update their systems.
Your IP should have arranged for the restriction on your house to be lifted so selling is now a viable option.
Good luck and I hope you are able to clear your records easily and move forwards with your debt free life.
Sharing from experiences of dealing with debt
There is a solution for everyone .... Just need to stay positive !