I would guess that the rate that they are paying are after legal deductions for R&D, losses, etc. so that the final figure of profit on which CT is payable ends up as 12.5 of the remaining figure which is 1-5% of the original profit before these legitimate deductions.
I think for me the whole issue is one of politicians in many countries now now seeking to create pariahs and scapegoats of individuals and companies that create wealth to take the spotlight from their failures. Failures to monitor a reckless financial system, failure to manage the fallout, failure to tackle government spending and failure to generate climate for growth.
There is of course a moral obligation to pay a fair share and many small companies are being hounded for tax revenue and being wrapped up in extra red tape which is not fair. Large company employ large number so they get preferential treatment from government, plus they make good photo opps for the re-election campaigns.
It is my opinion that taxing more stifles innovation and simply wastes the energy of individuals and companies in seeking ways not to pay or in the case of individuals who end up paying 50% plus for generating extra income generates the reaction - why bother. The fact that this revenue is going to prop up systems that remain incompetent and resistant to innovation is frustrating.
I am fully convinced if you removed 80% of politicians and leave those qualified to make laws and remove huge sections of pen pushing parts of the public service (including EU) it would not make a blind bit of difference to the running of the country.
So tax efficiently, tax lower and use the receipts wisely and all would be happier and better served not having to listen to infernal drivel of politicians. Put the resources in the productive end of the civil service front end.