I assume you've read Agatha Christie?! (Not necessarily great writing, but definitely great crime fiction).
How about Reginald Hill, who is a hugely underrated writer, IMO? Some of the later books (the ones with Franny Roote) got a bit overblown, but his books are generally sharp and funny. As well as the Dalziel and Pascoe books, he has a series featuring Luton-based PI Joe Sixsmith, and a couple of standalone books.
Another series I love (although they're a bit marmite and I've never managed to introduce them to anyone else successfully, partly because the first book is nowhere near as good as the others) is the Bryant and May one by Christopher Fowler. The conceit is that B&M are essentially golden age detectives who were assigned to the secretive Peculiar Crimes Unit during WW2, and were subsequently forgotten about (you have to turn a blind eye to some of the chronology as they would be well over 100 by now). They investigate anything that is deemed too weird or "specialist" for the normal police force, and the forgotten bits of London history and geography that make it into the books are a delight.
Have you read Kate Atkinson's Jackson Brodie books?
Less famous golden age/post-war writers you might like:
John Dickson Carr (locked room mysteries, a bit gothic at times)
Michael Innes (urbane and often bizarre in the Edmund Crispin style)
Gladys Mitchell (Mrs Bradley is a brilliant character!)
Anthony Berkeley
Freeman Wills Croft (a bit too focused on the minutiae of railway timetables, iykwim)
R. Austin Freeman (very early forensic investigations - so early, in fact, that you can get bundles on Kindle for peanuts)
GK Chesterton (possibly a bit too mystical for some)
Josephine Tey
More recently, you could also look at Simon Brett, Colin Dexter or Faith Martin.