Know two people who have just brought from Sean, both horses passed 5 stage vettings with bloods, very nice irish types seem to be quite genuine. As with any dealer go with you eyes wide open and always have a 5 stage vetting with bloods.
as said above be very very careful when dealing with some dealers as they are not all very forthcoming with the truth and are not interested in whether the horse will suit you or even be safe for you, but i expect there are some very good dealers just be aware