I have read that the first keyboard solo (harpsichord) on Rat Bat Blue is recorded at double speed for effect, so obviously 'a jam with some planning'. Play it at half speed to hear what it actually sounded like. Much of Deep Purple Mk.2's music was basically a riff with jamming. This is little different. It was how they made their money. The next track on WDWTWA was Place In Line, a classy slow blues with a shuffle outro and a slick and subtle guitar solo. Worth a listen.
Man dude, you shoulda took a nap before you taped this. This was the end of Purple and they weren't getting along and weren't even in the studio at the same time. Blackmore didn't contribute much so Lord did more solos on this album.