Der Q-Steuerabzug erfolgt tatsächlich offenbar zu Recht.
Shell selbst veröffentlicht dieses zur steuerlichen Behandlung:
"Taxation cash dividends
Cash dividends on A Shares will be subject to the deduction of Netherlands dividend withholding tax at the rate of 15%, which may be reduced in certain circumstances. Provided certain conditions are met, shareholders in receipt of A Share cash dividends may also be entitled to a non-payable dividend tax credit in the United Kingdom.
Shareholders resident in the United Kingdom, receiving cash dividends on B Shares through the Dividend Access Mechanism, are entitled to a tax credit. This tax credit is not repayable. Non-residents may also be entitled to a tax credit, if double tax arrangements between the United Kingdom and their country of residence so provide, or if they are eligible for relief given to non-residents with certain special connections with the United Kingdom or to nationals of states in the European Economic Area.
The amount of tax credit is 10/90ths of the cash dividend, the tax credit referable to the first quarter 2014 interim dividend of US$0.47 is US$0.05 per ordinary share and the dividend and tax credit together amount to US$0.52. The pounds sterling and euro equivalents will be announced on June 10, 2014."