As an incoming UK diplomat, Ivan Rogers is not subject to the EU revolving door rules. The UK has its own revolving door rules which govern UK civil servants when they leave the government, although these do not appear to apply to incoming appointees, only when officials leave government for a new external post.
Ivan Rogers is a seasoned UK diplomat who has made several trips through the revolving door. Prior to joining Barclays Capital, Ivan Rogers’ previous role was with Citigroup from 2006 to 2010. Before that he was Principal Private Secretary to Prime Minister Tony Blair 2003-06. From 1999-2003 he was Director of EU Policy and Strategy, and then Director of Budget and Tax Policy at HM Treasury. This was preceded by a spell as Chief of Staff to the Vice President of the European Commission (Leon Brittan) from 1996 to 1999. More information: http://www.number10.gov.uk/news/senior-adviser-appointed/
"Ivan Rogers is one of the most senior diplomats handling European affairs for the UK government. His move from the corporate finance sector back to government to become Prime Minister David Cameron's chief EU policy chief appears to have been unregulated, despite the risk that conflicts of interest could arise."