What you said about 'competitive advantage' is quite correct and is against the principles of 'free market capitalism', since the small local companies are not free to use the techniques the big internationals enjoy.
As for those who spout off about VAT and employee income tax, that must be challenged as soon as it is said.
VAT is not paid by the companies, it is paid by their customers. If VAT was doubled overnight, it would not affect the profits of the company, since all they do is collect it and pass it on to the government.
If income tax was doubled overnight then that too would not affect the profits of the companies. For the large companies to say that they are the ones who are paying VAT and income tax is like me saying, "because I didn't kill you today, that means that I've saved your life, and I'll save your life tomorrow as well, I'm so good to you."