All parts on Europe after the rain were played by John, except for the bassline. While it may sound somewhat electronic I'm quite convinced it's a bass guitar (hence Jake Durant played it) and not a synth. However, many seem to disagree with me so is there anyone who knows for sure?

According to the album liner notes Duncan Bridgeman played the bass part on this track. I would have thought if the bass part was played on a synth he would have been credited as playing synth.But then again...

Ah yes you're right it was Duncan.
But indeed, when the bassline was a synth, John probably would've played it himself since he did all the other instruments as well.