If both offers are for FSI then you have to be in London - period. Australia will still be a post-London option, but Australia to London (especially in FS) will be a very difficult move to make. Depending on the project you could complete a London stint in 2 - 3 years, half what you are thinking, and convincingly move as a Director level hire down under. On the basis of EY v Accenture, if this is FSI, then EY wins hands down. They simply have the pedigree in FS. The flow of business is still in favour of London, and most major projects within banking (especially those with a global footprint) will be directed from London.