I think you are greatly over estimating how much public opinion or image will matter in these talks on the european side of it. People are far more concerned that their industry is protected, their job is protected. A lot of good will is also squandered and when we look at the last time the mainland good will well ran dry, it was Greece and many European voters were no longer in favor of keeping the Greeks afloat after their theatrics.
The reason you'll see economics doing well is due to being connected for so many years, there are so many big industries behind this that not even the most craziest politician will try to break those down to nothing, the money behind it will break them otherwise.
Now the real talks are about the political side of it, the freedom to travel between EU nations we trade with and the financial aspect regarding projects the UK voted on, which they will be expected to pay for, same goes for British citizens (officials) working in the EU and their pension funds, the UK will try to recover money on other things. Those are the most loaded debates going forward.