The apartment really is an ideal location - on a lovely little side-street just off bustly Alameda de Hercules, with its amazing bars and cafes. The city centre - Cathedral etc. - are all walkable from here. The apartment itself is spacious with a beautiful roof terrace, would comfortably fit up to 4 people over its split levels.
Alberto's tips for eating, drinking and flamenco were all really helpful!
Only issue is check-out was 12pm, with no facility for storing bags in the foyer etc. until our evening flight. Fortunately a local hotel let us there left luggage room after asking nicely! :)