Seems odd, I always had to ask and sometimes had to pay! In fact I had to make a four figure settlement when the TC2 regime was introduced for our trade back in 2004, in respect of outstanding liabilities for the previous 6/7 years. Fortunately I had made returns every year, they just didn't shout loud enough to get paid. I was equally fortunate insofar as they didn't apply any interest or surcharges for late payment.