From further investigation - cheers RD - it looks like I've already buggered up the chronology of the 1982 'Socialist Thinkers – People Who History Made' lecture series so, with that in mind, I'll just plump for the Steve Coleman talk on Georgi Plekhanov as the next one to be uploaded.
From listening again to the Plekhanov talk, I'm guessing that it was the first in the series, followed by the Dietzgen talk already posted, and then the talk on Karl Kautsky:
First Part
DOWNLOAD LINK: Plekhanov and the Materialist Conception of History
FILE NAME: 03 pleknanov 1.mp3
FILE SIZE: ~60.57 megabytes
LENGTH:1:05:45
Second Part
DOWNLOAD LINK: Plekhanov and the Materialist Conception of History
FILE NAME: 04 plekanov part 2.mp3
FILE SIZE: ~34.20 megabytes
LENGTH: 37:07
Further Reading on Plekhanov:
