Yeah, that's fair - the big caveat with London is that you'll basically be renting in zone 2 outwards if optimising cost of living is in any way important to you. That's one of the tradeoffs I always forget when comparing Berlin and London.

Though to be fair, London being what it is, plenty of places in zone 2 still very much feel like bustling city living if that's your thing. Berlin, less so - once you're out of the central neighbourhoods it gets 'suburban' rather more quickly.