You would need to speak to your IP (not least because the inheritance may place you in a position to help close down the IVA).
IVA started March 2011, Completed March 2016 and certificate issued 11 days after final payment. It was not always easy but then some of the best decisions aren't.
It sounds reasonable and if your IP has the discretion they can do this. Otherwise it would require another meeting of creditors and they usually allow this anyway. Try and provide any backup you can such as quotes for the work needed.