Johnstan

I’m a UK resident receiving income from a foreign country. For example, I receive dividends from a Japanese corporation and from an Australian one. The tax return asks me to enter the “minimum foreign tax payable” (%) for these foreign dividends. But it gives no indication of where I can get that number from. The help page directs me to a document called Digest of Double Taxation Treaties. However, that document is about non-UK residents receiving UK-sourced income, which doesn't seem to be applicable. Can anyone help me solve this problem? Thanks in advance.