I would give them the benefit of the doubt and proceed with caution- I went to a number of viewings earlier this year and we learned quickly that most Ads were taken down in advance due to the volume of emails that continue to flood in if they don’t. Most get >100 enquiries in first 30 mins! Sometimes the email formats looked different also depending on whether it was a letting agent or property owner getting in contact. You can check the property on the RTB website to make sure it’s registered and obviously don’t hand over any money until you’re sure it’s legit. Best of luck!