You can use box 3 of SA100, if your only foreign income was untaxed foreign interest (of up to £2,000), put the amount (in UK pounds) in box 3 instead of filling in the Foreign’ pages.
You must put the name of the country where the interest arose in Any other information on page TR 7.
If it was more than £2,000, you’ll need to fill in the Foreign pages.
If your only foreign income was any interest in box 3 and dividends up to £2,000 and you’re claiming deduction relief, put the net amount of foreign dividends (in UK pounds) in box 6.
Put the foreign tax taken off in box 7. If your total dividend income (including UK and foreign dividends) is over £2,000 and you’re eligible to claim deduction relief or Foreign Tax Credit Relief, do not include the foreign dividend in this box.
Complete the Foreign pages instead.
Tax Return notes