Conversation so far:
What year was the record deal?
The Sweet signed a new record contract with EMI's Parlophone label.
Three bubblegum pop singles were released: "Lollipop Man" (September 1969.
What was the new lineup?
Guitarist Mick Stewart joined in 1969.

Question: what happened after he joined?
Self-contained rewrite: What happened after Mick joined?