Having a new car we send back the tax disc on the old one for a refund. We calculated that we would get £60 if we got it sent back by the end of January. However, we were not able to post it until the 31st january and so assumed it would be downgraded to £50. We were delighted when we received a cheque for £70 this morning. maybe we got the maths wrong but for whatever reason, it was a great surprise!