The one your refer to sold for approx £7800 inc commission premium. What was surprising about this auction was that the watch did not work and had no movement photos if I recall. That said it had the bones to be a great example once serviced and brought back to life.
I thought the price was steep as in my opinion these are worth around £6-10k working so there isn’t really any wiggle room for unforeseen expenses. I suppose though that if you’re willing to spend this much on a watch a few hundred or more for a donor movement (if needed) is a small price to pay to get the watch you want. The estimate was £1000-1500 so I was hoping I was going to come away with an exciting project.
It all comes down to supply and demand and if two people really wanted it - I can see why they would bid up to this price. They’re so hard to find that sometimes it is better to pay an inflated price today, instead of an even higher price when one next comes along as nobody quite knows when that might be…