Duncombe Hill is a lovely road - if you want a nice pub the Blythe Hill Tavern is a short walk away and Blythe Hill Fields is lovely. I appreciate the "greenness" around here
It is good for transport and the local shops have all you need - I tend to either get the bus to/from Lewisham for Sainsbury's or walk over the hill to tesco or walk to Lewisham if feeling energetic) You could also get the train to Surry Quays for Asda or to Canary Wharf or Croydon for Waitrose - plenty of choice. If you want a gym look at St Dunstans - think it is £25 per month for classes, use of gym and swimming. Only drawback is it is out of school hours only if you don't work I guess