It's tax efficiency, not avoidance
I'm fed up with all the muddled thinking about company tax avoidance. It is the duty of directors to run firms for the shareholders's benefit. They'd be negligent if they failed to organise business affairs in a tax-efficient manner.
As far as I know no one is suggesting companies have been acting illegally. If the current system doesn't produce the desired revenue, then it's up to Government to change the rules so that it does.