This was a great book - 'Moonlit Eyes' by Emma Blair (Time Warner paperbacks, London, 2002). I couldn't put it down.
This is about a black couple, New York saxaphonist Pee Wee Poston and his wife Beulah coming to live in Islington and living next door to Albert and Jess Sykes and their children Ellie and Paul. Pee Wee and Beulah have come to London in order to be near their son Julius, a high-flying diplomat at the American embassy. The Sykes are friendly and helpful to Pee Wee and Beulah, even though they see them as being in a class above them, and there is also the race issue.
War then breaks out. Son Paul is evacuated but is unhappy. He comes home, but it results in him getting killed. Ellie is heart-broken and blames herself a lot. Then tragically, a bomb hits the house and Ellie is also killed.
Albert goes to convalesce in a home supported by his trade union. He is really happy there, does lots of odd-jobs for the matron there and decides to stay. Meanwhile, Ellie and Julius fall in love.
At first, Albert is concerned about the race issue, but then he accepts them.
So, there are various tragedies throughout the book, and the book addresses various social issues, but there is a happy ending.