Not the fault of Amazon
Amazon ducks its responsibilities to UK taxpayers by shifting profits offshore using opaque corporate structures.
Amazon's responsibility to UK taxpayers is to obey UK tax law.
governments [need] to get together and rip up the international rule book that has been in place for nearly a century, and move instead toward something called 'unitary taxation'.
Precisely. If a government wants Amazon & their ilk to pay more tax, the solution is in their own hands. Change the laws that are preventing it. Moaning that they should pay more than the law requires because it would be "fair" is never going to cut it.
We've yet to see the claw back of tax avoided in the past like we have seen in France and Italy in connection with Amazon.
Avoiding tax is perfectly legal, it's tax evasion which isn't. If a company has avoided tax by exploiting loopholes in tax law, there's not much grounds for "clawing it back". Removing the loopholes for future payments is the way to go.
Tax law is like so many other old laws, every time someone finds a loophole, a government will draw up a band-aid law to close the loophole, and that often opens others. It's a pile of warts on warts on warts.