Over on BBC News there's a full page article on the BBC Radiophonic Workshop. A fair few vids with explanations of how some of the more recognizable sound effects were made.... There's a very short clip of a guy making a Dalek Voice on the EMS VCS3.
What with this, the multiple vids on youtube, the Alchemists of Sound docu and the many articles in SoundOnSound and other magazines I think the BBC Radiophonic Workshop is well covered for now. I wish we could get a few more vids on WDR or RTF or more information on the R.A.I. Phonology Studio... I'll have a hunt about see if I can find anything.