[nbevans]

6k is pretty typical for any premium apartments in London. That's actually pretty cheap for that location.

[lozenge]

Half of the population of the City of London (aka the square mile) is in the Barbican. There is hardly any location to compare it to.

[walthamstow]

There's quite a lot of housing just outside the City boundary in Shoreditch and Farringdon, the latter being easily comparable to Barbican as it's the next stop on the tube.