I wouldn’t choose US matters as you aren’t likely to be working on them unless there is a heavy element of the company/matter based in the U.K. Focus on the European deals and just think whether they might be U.K (eg are the companies/industries U.K. based). I am sure with a bit more subsequent research you’d find more detail if you weren’t sure.
Knowing matters that have happened means very little to be honest - the matter is in the past and you won’t be working on it. What you do need to think more about is the type of matters and why that appeals.
Alright thank you, that's a useful way to approach it