Pimlico is fab, nice and villagey, a real community yet so central - walkable to fun places in any direction - Battersea PS and Park, St James Park, Sloane Sq, Westminster Abbey....etc etc. Good choice. (Much more central and connected for transport than Chelsea!)
And I think we can claim a bit of Pimlico rd because it's so pretty. (Sometimes I even borrow the first half of Elizabeth St at a pinch if I'm feeling posh).
Your pick OP is not a bad choice, but the building is not as pleasant as the Erasmus (or Cureton st) linked up thread.