Hi Czarek
8.75% is the basic dividends rate of tax applied in the UK. The foreign tax credit is not referring to this.
If the UK has a tax treaty with another country, you need to review the article that applies to dividends. That article will declare the limit of relief.
For example the tax treaty with France has article 11 covering dividends and it states relief is limited to 15%.
This is the limit for foreign tax credit relief. The agreements between countries differ, which is why you need to confirm the agreed relief.
A list of treaties with the UK can be found at
Tax treaties.
Thank you