Conversation so far:
When were the Seekers discovered?
In May 1964, they travelled to the U.K. and upon arrival they were offered work by a London booking agency
Where was The Seekers from?
The Seekers were formed in 1962 in Melbourne.
What was The Seekers' first album?
Their debut album, Introducing the Seekers, was released in 1963
Does the Seekers article mention anything about Introducing the Seekers?
Their debut single was the traditional historic Australian bush ballad from 1894, Waltzing Matilda, which appeared in November and reached the Melbourne Top 40 singles chart
Who discovered The Seekers?
They were offered work by a London booking agency, the Grade Organisation.
Is there any other important data about The Seekers' discovery?
They signed there with World Record Club and issued a single

Question: What was the single?
Self-contained rewrite: What was the single issued by the Seekers after signing with World Records Club?