I've sold a few watches in the last weeks to take advantage of the weak pound, and didn't notice much softness at all.

I think people may be realising that vintage watches are somewhat like gold - limited supply and fundamental value.
If you spent $10,000 on US financial stocks three years ago you would have had very little enjoyment out of the stocks and very little money left today.
If you spent $10,000 on vintage watches you would have enjoyed them for three years and they still have some fundamental value....

I expect second hand modern luxury watches to have dropped more - I understand second hand modern ferraris, porsches et al have all dropped a lot, whilst vintage cars are keeping stronger.

Of course nothing at all is immune to the global economy but these days if you can hold an investment in your hands it means something!