Two points -
Firstly, most people on the Level 42 digest are ardent Jaydee fans because they love the early Level 42 sound. If you are after that one sound only a Jaydee can get it - it's a very distinctive tone. However, from Mark King's POV it wasn't actually the tone he wanted - and indeed he only ever used his Jaydee combined with a pretty heavy chorus effect, never 'dry'. The sound he was after was a combination of his heroes - Clarke and Pastorius, mostly Clarke. He sstarted with Jaydee because out shopping for equipment with his newly-signed advance money, he spotted one in a music store in London, it looked like his dreambass Alembic, but was within his price range. The Jaydee he bought had actually been made for Stanley Clarke but Clarke had thought it a gift and rejected it when it came with an invoice from the luthier.
It is no surprise then, that having reached a certain success level he dumped Jaydee for Alembic. Mark also used both filters wide open on his series II, with neck pickup on 3/4 volume and bridge on full. That for me isn't the optimum setting for cutting through the band mix, but it is the Mark King sound (and let's face it, he was prominent in the mix as the band's 'star' so could get away with it!) so I can see why the previous owner of this bass was trying to match it.
My second point is a simple price one - this bass is seriously overpriced, particularly in current market conditions. The last time I bought a Series II privately it cost me ?3K (2003), and even one with good as pretty as this and front and side leds should, in my opinion, be maxing out at ?4.5-5K ($7.5K). This is why the bass did not sell - not because it is a dog (any neck problem can be addressed, and I have rarely seen a more beautiful bass) but because the market didn't agree with the price.