James Ellroy said to the director of L.A. Confidential 'my book, your film' and that's the healthiest attitude to take. It's a different medium so the best thing is to let them get on with it and concentrate on the next novel. The Long Firm captures the essence of life in 60's London. If you mean by 'social and economic mindset' establishing a context to that period, then yes, I think that was how the process would start. Then lots of strange and eclectic research.
Details create a sense of wholeness.
It's finding the right language that's most important. The right words. Crime was as ugly then as it is now. There's just a lot more guns and drugs about. The violence in your book is of a more psychological nature in that it happens at the sidelines.