Please make sure that you get a document from the Thai bank stating the total amount was transferred from abroad for the purchase of Condo XYZ. Herein XYZ is the Condo number as appearing on the registration document. I understand that this is very important & is required by the Land department during the condo transfer to a foreign buyer.
Probably, you may have to mention it when the amount is transferred to Thailand from abroad( then only the Thai bank will issue such a document).