A company which has seven 51% subsidiaries has taxable total profits of £140,000 for the year to 31 May 2020. Dividends received in the year were £50,000. Calculate the corporation tax liability for the year and state the date (or dates) on which this tax is due to be paid, assuming that the company was "large" in the year to 31 May 2019 and either:

(a) all of the dividends received were intra-group dividends, or

(b) none of the dividends received were intra-group dividends.