Certificate of residence for dividends

I was in the process of completing the online application for a certificate of residence in the UK using the government gateway interface. I need the certificate because I have been taxed twice on the same dividend income (by both UK and Germany) and I want to claim back the tax from the German government (My tax residence is UK but the income arose from shares held in Germany). I have dividend income from 12 different German companies all of which were double taxed. However the government gateway interface only allows me to enter 5 companies. What should I do? Should I request the certificate having entered only 5 of the 12 affected companies? Should I write some aggregate amount into the box which is actually designed for data from one company only?

Hi,
You do not need to declare to HMRC, each and every company you receive dividends from. The certificate of residence will cover all of the German sources of income.  
In the freehand notes box, you could state your have a total of £x amount of dividends from 12 companies, having mentions 5 of them.
Thank you.