What are the upsides for British science from Brexit? This is a companion question to Why do most scientists think Brexit is bad for British science?. Based on this meta discussion, it was suggested that I ask a new question about potential upsides of Brexit...
From the answers to that question about Brexit, it sounds like there are no upsides to British science. However, there are still roughly 12% of UK researchers who think the UK should exit the EU. It seems that these 12% must see something positive from Brexit, otherwise they would not be voting to leave.
What could these positives be? Or are there no positives, and they are just more optimistic that the UK government will provide the political support to let British science emerge unscathed and / or they think the gains elsewhere outweigh the losses?
Only thing I've seen about this is Royal Society president Venkatraman Ramakrishnan saying:

Will Brexit open up any new opportunities for UK science? Are there burdensome EU regulations you’ll be glad to see go? Will collaboration with scientists in non-EU countries, like the US or China, become easier? Will tranches of non-EU funding become accessible?
The only thing I can say is that if you have new technologies and you need to make regulations where current regulations don’t exist, then it’s easier for a single country. Britain is very rational about balancing risks and benefits. Its easier for one country to move fast. This is a sort of theoretical, possibly marginal benefit. Whereas the actual risks and drawbacks of Brexit are much more real and immediate.

However this sounds extremely marginal. Unless these 12% of UK researchers know in advance that they're going to come up with groundbreaking new technologies for which current regulations don't exist, it's hard to believe that 12% of UK researchers would vote to leave for this reason.
I am interested in all positives, short-term or long-term.
There are no upsides for British science from Brexit. 

This is a corollary of the almost certain fact that there are no upsides for British society from Brexit.

Science funding has never been a priority of the current government and I hardly expect that situation to change once we leave with no deal. In truth, we are cutting off access to collaborations (e.g. ESA) that we can never hope to compete with as a single, tiny nation with a floundering economy.

To understand, then, why in spite of this 12% of UK researchers still voted to Leave, you have to realise that when the referendum was held, a large number of people in the country used their vote as a protest-- against the establishment, against immigration and against the perceived power of the EU parliament over our own. 

People were generally misled by self-serving politicians that societal benefits would occur once we left the EU-- more control over our laws for instance, forgetting that we elect MEPs to the European parliament so have just as much say in EU law as our own. They perhaps believed that there would be more money for the NHS, even though the reason the NHS is underfunded is not due to the EU but due to the same Conservative government that has been in power for the last eight years.

I am certain that not even the politicians gunning for Leave actually thought the benefits they claimed would ever happen-- they simply picked the side they thought would gain them votes, and for many Conservative MPs with very right wing, anti-immigration constituencies this was Leave.

For the reasons I have outlined above (and doubtless many more), a person may have decided to vote to leave. The vote was a very personal decision for a lot of people and as Thomas says, scientists are people too. The 12% that you quote likely voted to leave based on non--scientific issues, just as I voted to remain based on non--scientific issues, namely that I believe that a diverse and multicultural society is better and more productive for everyone, I am averse to hatred and xenophobia and I like going on holiday to other EU countries without needing a visa.

If our politicians were capable of thinking about something other than their own ratings in the polls, they might have been able to negotiate a sensible leaving deal, with every eventuality considered and taken care of. In that case, I would be less worried about the effects of leaving on British science.

However, we are now faced with the prospect of a no-deal Brexit. The government is trying to hide the fact that it is stockpiling food and mobilising the army to prepare for the worst (presumably they are afraid of rioting and looting).

People's wilful ignorance of the wholly negative effects of Brexit will be sorely tested when food rots in the fields with no EU workers to harvest it, when a black market begins for "luxuries" like cheese and chocolate, and when their relatives die in hospital because their medicine is on the other side of the border. 

Society will suffer. Science will suffer.

I am aware that this is an emotive and partisan answer, but Brexit is a very emotional subject for most British people. I am still living in hope that one day soon we will have a general election, form a sensible government and call the whole thing off.