It would not be the end of the world if you declared these as UK dividends on the main part of the self assessment return as the company whom handles your portfolio is UK based. and you are NOT expected to break these down into individual returns and its such a small amount. And I assume all were paid to you in sterling?
If it was several thousands and direct foreign investments then you would have to use the foreign pages due to the different currencies and tax rates
Let me know if I can assist further