Yes, it is annoying that Amazon lump reviews of all the different versions of a product together.
I'm sure you're aware of this, but if you're a lover of radio drama, the BBC have a dedicated radio station: BBC Radio 4 Extra, which plays nothing but drama (and comedy) 24h a day, and it's all available world-wide via the BBC iPlayer web site,
http://www.bbc.co.uk/iplayer