No - as a creditor with security they can ask for their payments to be reassessed at any time, but this should be in a polite manner and not one of harrasment.
When I was entering into my IVA and egg were talking about taking me to court I remember my IVA firm said they would get the iVA in first but if there was any risk of a charging order they would go to court and get it stopped whilst the IVA negoatiations were taking place. I think it was called an interim order or something. I am surprised that this did not happen in this case.