I moved from London in the late 90s. Lived in Queenscliff (1st headland to the north of Manly) for the first couple of years. Have lived in the Northern Beaches ever since. Would recommend. Expensive, but London is a better urban location than Sydney and living somewhere like Manly is taking advantage of what Sydney has to offer which London simply doesn't. I would recommend any Londoner who moves to Sydney to live in Manly and/or Bondi at least once because why move here and not experience living in a beach suburb, it's not like you can't decide to move somewhere else later.

Manly has the best night life in the NBs, particularly if you are in your 20s/early 30s without family. Five large drinking establishments, heaps of restaurants and smaller bars etc (watch the waistline). Coffee staring out to sea of a morning then ferry into the city. Beaches of course. Heaps of sporting facilities nearby. Very active cycling scene as well, both road and MTB.