Pardon me, but are you male? And will this watch be for you? According to Chrono 24, the case measures 15.5mm X 16mm. I have "a few" vintage men's watches. but that is REALLY tiny! That's about the size of a ladies watch (and that's why I asked your gender).
Also, judging by vintage IWC's that successfully sold on eBay, the price seems a little too steep for my comfort, in spite of its being in "excellent" condition,,,,whatever THAT means!
I'm also uncomfortable with the fact that they don't say when it was last serviced (in spite of the "6 month warranty").
If it were up to me, I'd say keep looking.