You can monitor it on the Insolvency Service website but they have up to 3 months from completion to remove it. Beyond that there is a contact option on their website.
Mine took exactly 3 months to the day but others have been quicker. It's the luck of the draw and that 3 months felt like a year to me...lol.
If you haven't gone within a couple of weeks you are one of the lucky (!) ones who will wait the three months to the day -- it seems to depend upon who picks up your docket. In the meantime, however, the IVA should be marked as completed --- look for that clue that you are in the process.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014