Here are a couple of videos relating to Alan Blumlein’s work. The first one here is a test of stereo recording from the EMI Archives:
This next one shows Neville Thiele from the AES talking about Blumlein:
Another resource from AES has some great history of stereophonic sound and shows that Bell Labs in USA were also experimenting with stereo sound around the same time as Blumlein, but in different continents:
http://www.aes.org/aeshc/docs/recording.technology.history/stereo.html