Glad you've discovered it, Diane.
I had never seen it before returning to Scotland to live five years ago, after 15 years exile south of the border. I was channel-hopping one evening and stumbled across it. It took several minutes of incredulous head-scratching before the penny dropped that it's a spoof.
I love it! Every character is at least plausible, and beautifully portrayed, Particular favourites are (of course) Chief Cameron Miekelson, Officer Karen, and Ken Beattie, but they all have their strengths, as do the assorted bams, tubes and neds.
Enjoy!