I have checked my national insurance gaps and have a couple that I would like to pay as it's not very much. But, actually paying it is causing me trouble! I have found a page where it gives a sort code and an account number - but it then asks for your reference number to be used as a reference. It says this is on your bill...now, try as I might I cannot figure out where to find this number. Any ideas? Has anyone actually paid a gap in recent times? I thought it would be a nice easy online form...