Neither bad weather nor delays in the Christmas post will be accepted as excuses by Companies House or HM Revenue & Customs.
Many small companies have a 31 March year end and need to file their accounts at Companies House by 31 December 2015. Sole traders and partnerships who pay income tax under Self Assessment need to prepare accounts and file a return by 31 January 2016. If they leave things to the last minute and then we have a spell of extremely bad weather, then the deadline can be missed, so you are advised to get going now with collecting your records and handing them in to your accountant.