Both sides were adamant that voting Leave meant leaving the single market and the customs union

Perhaps, but very few - campaigners or voters - understood what it meant, I suggest. I offer in evidence three things

Firstly, the contents of the BBC "Have Your Say" messages around Brexit. You should form your own opinion, but it is clear to me many posters still do not know what is 'customs union' and what is 'single market'. And they are the ones involved enough to bother to post.

Secondly, much of what both the Leave and Remain camp said was ignored. Why should anyone give more credence to Osborne's view about leaving the CU/SM than his emergency budget? Discount the latter and you may well discount the former. Similarly, Farage and co made great play of having a bespoke UK-EU agreement. No one, I would suggest, had any idea how that would 'compare and contrast' with the CU/SM.

Thirdly, it may have slowed a bit, but the first few months revealed unintended consequence after unintended consequence. Did most people - campaigners or voters - realise the Irish border question was linked into the CU/SM question? Even now there is much denial of that. So if the campaigners didn't fully understand the consequences it is a bit harsh to expect all the voters to.

I am with Dave: we know how people voted on the given question. Using Iains' current favourite term, claiming you know what they felt about anything beyond that question is opinion.