When I bought this single back in the 70's, the 'B' side had a song called Amoureuse, by Kiki Dee. However, the label on both sides said Don't Go Breaking My Heart. Before I played the 'B' side, I thought it might just have been an instrumental of the 'A' side, but nope. Twas Kiki Dee singing Amoureuse. Odd dont you think? Production error perhaps?
I have a similarly mislabelled single by a different artist. If you look closely at the edge of the record there's an etching of numbers. The A side will have a different number to the B side.
Not uncommon, according to Record Collector. Mine isn't on their list of valuable examples.