I agree that UK had better get on with it because that is what EU members will be doing.
I only read the Spanish papers, but La Vanguardia quoted Churchill today, when it said "When someone does something stupid, don't laugh. It may present you with an opportunity"
Nowhere near an exact quote, but I think that you get the meaning.
Big business will be looking for opportunities. Now, they are looking at EU offers. NOW!
You have no government, yet. Get cracking!
The new government will have to make business life more attractive in the UK than in the EU. Let the immigrants be. They will not come if life is more attractive, elsewhere.