Which is better for moving into litigation - thinking large London-based law firm (UK or US), or even barristers' chambers

I'm looking to make a move to the UK (I have a UK passport) but my US experience (5yrs) is mostly small firm, so am hoping that top grades (fingers crossed) in a litigation oriented LLM from a top school might help.

Also, what are one's chances of getting into Oxford, Cambridge, LSE, UCL or King's if one was not in the top 10% of one's class? I was top 20% in my LLB, and top 40% in my JD.

Thanks.

why do you have an llb and a jd? please elaborate...

Hi ED (funny abbreviation no?):

I moved to the US 8 years ago with my American fiance and had to do the JD to stand a chance of getting a job here.