taxation, PAYE, FBI, File By Internet, HMRC, Works Number Update, WNU e-service developers DecisionSoft Ltd HMRC 2003-06-30 2005-09-30 text/xml http://www.w3.org/2001/XMLSchema XML Schema, W3C Recommendation 2001 [ISO 639-2/B] ENG HMRC core-v2-0 IRenvelope (C) Crown Copyright 2001-2005 Economics, Finance and Tax Works Number Update message