I'll agree with reviewer Paul Scales on this. It is too complicated.
But I'd go further. The whole thing seems to be based on a rather implausible series of events relating to the history of the car central to the story going back several years. Anybody who has watched detective shows will have heard someone at one point say something like "I don't believe in coincidences". Well, nobody says that in this episode but they wouldn't dare as the entire complicated chained plot line is based on one coincidence after the other with much of that not being revealed until the end. The Eddy Nero connection with the car towards the end (glossed over really quickly) was the final straw as far as I was concerned.
My wife and I discussed this episode after viewing it and even the following day after reflecting on it a bit and decided in the end that, really, much of this simply doesn't make a lot of sense.
Just one example: at one point DCI Box tells Morse and Thursday to "leave it to me" and clearly removes them from any more involvement in the case. And yet in the next scene, there the two of them are still conducting inquiries. We though, "gee, they're really going to be in trouble when Box finds out" Yet a few scenes later it seems that Box has absolutely no problem with Morse and Thursday are still investigating and implicitly they have his approval.
Time and time again Box tells Morse to keep out of it. Time and time again Morse ignores him. In any real life situation, Morse would have been dismissed, transferred or up on disciplinary charges for the way he was ignoring explicit orders. But not in Oxford.
As to the use of coincidences.... last week we had the implausible coincidence of Morse stumbling across the bodies of not one but two missing people in two quite different places. A little far fetched perhaps?
Sorry, but this is one of the poorest episodes in my recollection.
As always, well acted but the writers need to up their game and not just coast on acting and directing alone.