Herbekj, you can call the UK call centre direct - 0870 240 1170. I was told the request had to be raised online so there is an audit trail but I definitely wouldn't bother with their foreign call centre!
They are doing this in the mistaken belief that they are helping you ---- by confirming to searchers that the IVA showing has been completed. Which IS good in that final year between completion and credit file clearance.
What they should do, when they enter the NOC, is give it an automatic "shelf life", so that it drops off at the same time as the IVA.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014