As mentioned elsewhere due to a very small amount of non PAYE (ESPP) income Revenue in their wisdom have me classed as self assessed for 2010 so my return is due. But I lost my ROS certificate and need a replacement and am awaiting something in the post to retrieve this. Obviously if it doesn't arrive soon I won't have the ROS/November 15th extension option. In that case I must make the return and payment by the 31st. In that case is it possible to drop the form/payment into a letterbox somewhere on the over the bank holiday weekend or, in practice, does it have to be in by close of business on the Friday?