Comedy drama play would be The Fishing Party from the 70s. Nuts In May still gets shown and talked about but the earlier TFP was just as off beat and funny. The 70s was fantastic for one off gems like these.
Sitcom wise, Still Game seems peculiarly absent from the screen and as a result, the top sitcom lists. Ever Decreasing Circles I'll agree with, and I think The New Statesman is undervalued as is The Brittas Empire among others.