I submitted my 2015 tax return [regular tax return] for March 2014 to February 2015 period, by due date in November 2015. No problems and monies due paid over. I subsequently discovered that I was supposed to have submitted as a Provisional Taxpayer, not as a regular taxpayer. I now have to do another tax return, due 29th January 2016 [today!!]. I am registered as a Provisional taxpayer now but am unsure as to which Provisional period I am supposed to be choosing from the list that pops up. Should it be 2015, Period 2, or should it be 2016, Period 1? Also, do I declare last 6 months earnings only or last 6 months plus the upcoming 6 months [estimates]. How will this crossover from regular taxpayer to provisional taxpayer affect monies owed or due? Your advice will be very welcome.