Hi Blue Toffee. I've only just come on-line and seen your thread.
I went to YouTube and had a look at Diana. She has quite a husky sort of voice doesn't she. A bit like Cleo Lane do you think?
Not quite the range of Cleo Lane, but haunting, and her piano skills are amazing. Her guitarist and violinist would have given Stephanie Grapelli and Django Rheinhart a good run for their money too.
I think I was born in the wrong era BT. I really like the big band sounds of the 30's and 40's with Glenn Miller, Artie Shaw, The Dorsey Brothers, Benny Goodman, etc plus, of course, the singers that went with them.
I have a number of CD's and DVD's featuring them and I'm a sucker for biopics of that era.