How do I remove the winder from Pierre Cardin Diamonds watch? I think the waterproof seal has perished and have condensation on face that needs to be cleaned off. There appears to be a 'collar' at the halfway point between movement and winder does it unscrew from here if I hold the collar static?

Better get it dried up and serviced asap, as the moisture might have got into the movement. You dont want rust to be your next problem. But, some screw some dont....most people bring in the crown in one hand and the timepeice in the other-broken. If I'm thinking of the right watch, there is a release point inside the case that releases the stem.