Possible Clues:

• Borough in southeast Greater London
• Detective, hard on upset mum in London borough
• London district reached by a southern extension of the Docklands Light Railway in 1999
• London borough whose NHS choir (with 45) had a 2015 9 10 with A Bridge Over You
• A terminus on the Docklands Light Railway
• London district
• I am Welsh, having relocated to part of London
• Wells protagonist from London borough
• South London district
• South London borough