I would take to the hills in search of the Shaolin monastery (bruce wayne style), spend as long as it takes to become like that dude from assassin creed. Then return to the UK with my fake identity and take a course in book keeping/accounts. Once completed, I would take to the streets for a few years (or as long as it takes) to become a small time conman whilst studying body language and social psychology at the side.
Once I felt i had all the necessary skills I would seek a job as a bank clerk and slowly work my way up to branch manager. I'd do this by using my impeccable people skills/body language/confidence/intergrity (shaolin). Then, one night locking up, I'd use my shaolin skills I'd strike...leaving the whole world wondering how the fudge a simple and honest man carried out the largest theft in history.