The Information Gateway Online Reporter (IGOR), has now been updated to allow both registration and reporting under the UK IGA. This includes both standard reporting under the UK IGA and reporting under the Alternative Reporting Regime (ARR).
Further information relating to reporting under the UK IGA can be in Bulletin 2015/5 published on the following page:
http://www.gov.gg/article/109356/Intergovernmental-Agreements-FATCA
Full documentation in relation to the UK schema is accessible from IGOR at: