Alarms bell ring as soon as offshore is mentionned. It could be legit tho, so if it's a Zed you like I'd still consider it, just be extra cautious. In addition to the above advice, I'd check the chassis number when you go to see it to make sure it matches the reg.
If know the car's not stolen, and see the log book and it's signed over to you, I struggle to see how it could be a scam. Scamsters are getting better tho