Thug Seán oraiste dom.
Could this translation follow a different English construct and say, "Seán gave an orange to Mary"? To me it's a more logical construct, since the direct object is really "orange" which is "given" to Mary, and Mary becomes the indirect object. It also more closely follows the Irish construct, and it feels like the way I would say it...but I'm sure there are many who would say it they way it was originally translated here.
Dale D