Just mentioend as something of passing interest: Radio 4 Extra is running an adaptation of the children's classic The Silver Sword, and on the programme page there's a nice photo of Barry Letts (Pertwee era producer) and Frazer Hines (Troughton companion) from a 1957 Tv version.
http://www.bbc.co.uk/blogs/radio4/2011/04/the_silver_sword_comes_to_radi.html
http://www.bbc.co.uk/blogs/radio4/2011/04/the_silver_sword_comes_to_radi.html