The National Library of Australia has recordings of 3 of Bert's illustrated lectures. There's Industrial songs with recordings (some from The Iron Muse) and Erotic folk song and Folk Songs of England with Bert singing the songs himself.

https://trove.nla.gov.au/work/205639037?q=a+l+lloyd&c=music&versionId=225709360

If you click where it says View Online, it takes you to a disclaimer and then you can listen/download the audio.