Thanks for the tip, 57! I'll try doing that when watching British police drama series on HBO and Netflix. I'm very familiar with the Lancashire and Yorkshire accents but I do have some trouble understanding the London/Cockney accent if the actors speak very quickly.
Yes, exactly! The last episode I saw, where he drops in on his old partner, I had to run the PVR back three times and I still couldn't make out what Ali said so I gave up and carried on. Like you said, he spoke much clearer when the scenes flashed back to when he was a young detective. I just hope it wastn't an important point in the storyline!