probably ridiculous, but after getting visa what do i take to the airport?

[rsd 0]

I take passport, large white packet, and the xray CD. Do I take anything else? Also as an immigrant which card do I fill in on the plane, and which line do I get in upon arrival?

[Nich-Nick 3,354]

There is only one form on the plane now--customs declaration. Everybody fills that one out.

Which line? You are still a British visitor, so Visitor line. You might want to ask an attendant if there is a special line for new immigrants. A few airports might have that.