Assuming the turnout and sentiments from 1/7/2016 (the micorosimulation has 3-month resolution, so this is the data which is the closest to the referendum) for the population demographics from 1/1/2019, I get 52% for Leave. (corrected, sorry - I previously copied the old result I rerun as a test)
The past decided about the future.
People have changed their mind. The generation which overwhelmingly voted to join the EC in the 1970s rejected the EU. Who changed more? the EU or the people?
Britain always had an ambivalent attitude towards continental Europe integration. We never fit in this structure. Both sides will be happier going their own way.
We'll still be friendly neighbours, after all.