I'd optimise to be closer to the office over the airport because you'll be going to the office at least once a week (and more when you're on the beach, doing training or doing a London based project) vs. to the airport where you'll be going a maximum of once a week and many weeks not at all.
I'd definitely suggest living in London- it will make it easier to go to evening social events and will come in handy on London based projects.
When I was consulting, South London (Southwark, Borough, London Bridge) and West London (Earls Court, Barons Court, West Kensington, Chiswick for those with families) were popular. West Hampstead too.
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