Always better to post the actual photos rather than the link but the seller gives nothing away in his description and you need to look carefully at the photos.
There's no indication of how it’s running, other than 'fair condition' or when it was serviced. The sweep second has moved in the photos so it’s probably running.
On the positive side, the crystal is signed which is generally a good sign. The buckle looks both old and original. The dial, in my opinion, is original and the case doesn’t seem polished. The fact that the strap is old would support that, for me.
The 562 movement looks clean and I’d guess that the crown might be original. I can’t see the details of the caseback but I’d guess it’s a 166.*** with a diameter of about 34.5. You’ll probably have to factor in a service for £100-150, and hope the parts are okay on this 55 year old watch.
There are already a number of bids in and with a day to go, I’d expect the price to rise by £100-£200. The seller is only selling this one watch and is probably not a dealer. His eBay reputation looks okay but it doesn’t say what he sold previously and he hasn’t traded since May 2019.
So, do you feel lucky?
