I figured out most of the chords for "Rockaria!" this evening (up until ~2:39), and when I was typing out the chords in the same document where I have my (still incomplete) transcription of the lyrics, I noticed a near quotation. Near the middle of the song, there's the phrase "you got nothin' to lose." This is very similar to "ain't got nothin' to lose" in Chuck Berry's "Roll over Beethoven" (or "I ain't got nothin' to lose" in ELO's cover).
By itself, the resemblance isn't very convincing, but Chuck Berry is mentioned by name later in "Rockaria!" ("the orchestra were playing all Chuck Berry's greatest tunes"), so the similarity is probably more than just coincidence.
