The liner notes explain that the song appeared on the EP Wall's Ice Cream, which consisted of tracks from various Apple Records artists and was released in the U.K. on 18 July 1969. Badfinger was credited under its original name, The Iveys.
The song was written by Tom Evans (guitarist and later bassist in the group), but aside from that, I can't find any more information about it. I'm assuming that the Pianet was played by Pete Ham, who was the lead guitarist but who also played keyboards on some of the band's songs. Judging by the time period, I would guess that the specific Pianet is a model N, which seems to be the predominant model after 1965 or so.