In the long term it is difficult to see for an easy replacement for the city of London where Russian business is concerned. In this case "to see for" (although, like the commenters above said, is grammatically incorrect) can mean imagine. They're saying that they can't imagine a long term replace for London where Russian business is concerned. Now "where Russian business is concerned" means that the entire sentence is talking about Russian business. So the previous statement refers to Russian business. Another way to say this sentence is: "It is difficult to see a long term Russian business replacement for the city of London"

I didn't write the sentence. I quoted it from voa. Maybe it is a grammatically wrong sentence, since I don't understand it.

It is hard to figure out how to correct your sentence since the grammar is wrong in different places.

Take another look at your sentence. There's something not right here.