As Christmas presents go, it was far from ideal. In December 2015, three days before Christmas, an Irish GP received a letter from the Revenue Commissioners, demanding €106,000 in back payments. This was just the raw assessment – penalties and interest would propel the figure further north. The assessment covered a three-year period from the start of 2011 to the end of 2013 and related to an ongoing Revenue probe of the structures employed by doctors to manage their business interests.   The Revenue’s investigation into the tax affairs of highly paid medical consultants was well underway at that point,…