 Complete the following phrase:  Towards the conclusion of the eleventh series broadcast, applications for the twelfth series were made available in December 2015, with production staff assessing applicants between January and February 2016. Work on filming the series took place from late Spring to early Summer, once assessments had determined which eighteen applicants would form the final line-up. Both the filming and broadcast schedule for this series had to take into account three major events receiving live TV coverage during 2016  the UK government had announced in 2015 that they would be holding a major referendum pertaining to the future of the 