No, I'm not a lawyer.
But I do value precision, and I would argue that the phrase 'political facts' is an oxymoron in itself, since politics encompasses a vast spectrum of opinion, even within the Government (any given government but particularly this one, imo).
This Government, for instance, has also said that 'Brexit means Brexit'. Is that a political fact? Does it have weight and value because it was the Government who said it? If not why not? The Government is also now saying that they intend to keep us out of the customs union and single market, because that is what people voted for and is the only way to deliver on the result of the referendum. So has that become a fact now too? Because demonstrably it isn't true.
I would also argue that political facts, if that's a phrase you're comfortable with, occupy contested territory that is open to interpretation, whereas legal facts don't (not if we're talking about legal instruments rather than case law and precedent, anyway). That's not to say the law is always 'right' and we can always challenge ideas about what it should be and can change it if necessary, but that's a different thing.
I also value probity and, in a situation such as this, I do think the law should be where the buck stops and the decision is made. It's not as though the Cameron government didn't know the difference in law between a binding and an advisory referendum. The mere fact that they misrepresented the position in their leaflet is a solid legal argument imo (but of course IANAL!) for setting aside the referendum result as tainted. If the result had gone the other way, I am sure that's what Farage would have demanded (forgetting, of course, the leaflets he was putting through doors 'informing' us all about Turkey's impending entry into the EU).
There is so much more about how the referendum was conducted that has also passed from the status of legal fact to politically contested opinion, seemingly in the blinking of an eye, that I wonder how we can rely on anything if this is to be the new way of conducting national affairs - and that seems to me to undermine democracy rather than the reverse.
It's nice to have an intelligent conversation about this stuff. Thank you, Innocence.