That depends. Oranges are oranges. There is probably not much difference in regulations between different countries. Though, being an agricultural product, I am not even sure about that. Medicines and other chemicals, meat and dairy products, electrical goods, non-material goods such as services, information and software may be more difficult.

Note that I said "may be", not "are". You may say they are not and you may well be right. But how do you know? How can you be sure? The situation may change at any moment as countries change their regulations, as the UK has repeatedly indicated it wants to do in diverging from EU rules. You need someone whose job it is to constantly monitor the situation in all your export markets. In other words, additional costs to your business.

But, most importantly, as I have pointed out several times in this forum, there is a bigger difference between "nothing" and "a little" than there is between "a little" and "a lot". A million is only a million times bigger than 1, but 1 is an infinity times bigger than zero. For a business that has evolved in an environment where they have never had to deal with such challenges, a change from "nothing" to "something" is a HUGE change. A qualitative change, if you will. A completely new way of thinking. The British fishermen being "caught by surprise" (despite being warned many times but dismissing all warnings as "project fear") are an excellent example. In comparison, a change from "something" to "something more" is merely a quantitative change.

<political, feel free to ignore>

The EU is a protectionist bloc with a very high tariff barrier at its perimeter (and a tariff schedule that protected German and French industries but weren't well suited to the UK economy), it's hardly a beacon of free trade.

It is striking how the British tabloid propaganda machine has permeated regular folks' thinking. Just use words like "protectionist" as pejorative, without giving any explanation or context, or claim it helps "the others" but not "us", again without providing any proof, and they will parrot it without thinking. Then you can manipulate them into doing anything, including acting against their own interests. All you need to do is conjure an external enemy and foster the "us and them" mentality.

Of course the EU is protectionist. No one has ever said otherwise. Every market protects itself. What the Single Market has achieved is absolutely remarkable: it replaced 28 (now 27) individual protectionist markets with one. It did not erect any new barriers, but it removed barriers among the members. A model so successful it has been replicated many times around the world. A model the UK had benefited from HUGELY, rising from "the sick man of Europe" to the 5th richest country in the world. (Note that we have dropped down that rank after the Brexit vote. Depending on what measure you apply, we are now between 7th and 11th.)

The UK paid an EU membership fee higher than tariffs for the "luck and privilege" of trading without tariffs.

I have yet to see a country that imposes less than 0.4% import tariffs. Because that's how much our EU membership had cost us. Even if such a hypothetical utopian country existed, there are non-tariff barriers. As "a Director of a UK manufacturing company that traded right around the world", I am sure you are fully aware of that.

Furthermore import tariffs are money going in to the UK treasury where they are used to pay for the National Health Service, Education, Social Services, ...

Another popular British tabloid trope. Yes, it is money going to the treasury. But where from? The nasty foreigners? No, it is money paid to the country's treasury by... its own citizens!

Tariffs are not a source of income. It is not money flowing into the country. It is money flowing from the citizens to the government. You are right, a left-wing, centrist or a moderate-right government would spend it on public services. Not our current cohort we've had in power for over a decade, who have an ideological aversion to public services and who, as we have seen especially in the past year, have no qualms about shovelling billions of public money to private hands, with nothing or very little to show for it.

As you say, given a choice between the two above I know which I'd rather fund.
</political>