The classic stories described in the article may have died out in print form, but many of the tropes live on healthily in British TV. There's a vast range of charismatic, rationally insightful detectives to choose from. Granted, a lot of them are police officers which isn't true to the spirit of the article, but many are amateurs. I saw the genre referred to once as "cosy mystery" which pretty much hits it on the head (with, presumably, a candlestick.)

Do you mean like Ludwig? What else? I'm not in the UK, so often only see the best of British TV after someone has recommended it to me and I can go hunt it out.