Complex sentence: While attempting to get the band a record deal, Joe Boyd returned (and produced) with the group to Sound Techniques studios, to record a demo tape to be given to various record labels, one of the songs recorded was "Interstellar Overdrive".
Split into simpler sentences: While attempting to get the band a record deal, Joe Boyd returned (and produced) with the group to Sound Techniques studios. There, the band recorded a demo tape which was to be given to various record labels, one of the songs that features on the tape was "Interstellar Overdrive".