Raggytash I believe I posted exchange rates pound/euro for a considerable time period already.
pound euro Dec    28 2008 = 1.0229
          July   16 2015 = 1.4294 (max value since around Nov. 2007)
          June   13 2016 = 1.2639
          June   24 2016 = 1.2254 (Day after referendum)

As I stated the decline started before the referendum
pound/euro graph since 2000 .

When it comes to exchange rates averages are totally meaningless.
Who deals in currencies on average values? Answer No one