Does anyone know what US firms are classified as 'sateleite offices' in London. Thanks
This provides overview of all the firms in London. In terms of applications I'd say ones which don't offer training contracts. Further firms really only focussed in the transactional finance related space, especially PE

US firms in the UK - Chambers Student Guide
The student’s guide to careers in the law. Gives the truth about law firms and the Bar. Based on thousands of interviews with trainees, pupils and market sources, this site offers the full package of careers advice to anyone entering the legal profession.