I remember when buying a new Macan a few years ago they didn't have what I wanted, but within days, surprise, surprise, they'd found a cancelled order that matched. It happens all the time.
Now, whether the Grenadier agents will match cancelled cars to requirements from the queue of orders, remains to be seen. Maybe INEOS has a policy on this. My guess is that the agents would gladly sell a cancelled model to a showroom browser, but I suspect their hands will be tied somewhat since the sales contract is with INEOS, not with the agent.
That said, given the delays, INEOS might be minded to cut the agents some slack in this respect. There's bound to be some aftermarket sales activity, - flipping etc, and the agents will want to deal as much as anyone.
I'm sure many of us will be watching the aftermarket with interest. I'm looking forward to getting my car. If it lives up to expectations, I'll keep it. If not, I'll probably sell if I can find a willing buyer. Having driven one, I don't expect to be disappointed, but I'm hoping that the after sales experience is much better than this final production logjam.
My concern is that INEOS can control the market somewhat by drip-feeding demand. Managing production streams is a delicate operation, however, as INEOS has discovered. Better to concentrate on quality and let the market look after itself. Every cancellation represents an expectation that hasn't been met and that isn't good business.