Seller was originally stating he wouldn't refund as 30 days has elapsed, but as the conversation has moved on to me contacting eBay asking what I'd have to do if I suspected they are fake (i.e. what evidence would I need to collect and at who's cost) he's now saying he will accept a return. Thing is I'd just like some people more knowledgable than me to give me some comfort that I'm not being unreasonable in thinking they might be fake.
Personally I would engage pragmatism mode. If he is offering refunds, take him up on it. Let others put the Fake Watch World to rights.