And a quick quote from OCR B, MEI:
"For the 2017 A levels students will require a calculator that can calculate Binomial and Normal probabilities directly from values. The minimum standard for this is an advanced scientific calculator, such as the Casio 991EX ClassWiz or the TI-30X Pro; however, graphical calculators have this facility along with the additional advantage of being able to plot the graphs of functions....", although this is the same across all UK exam boards.