Brussels Art Auctions sells on 13 June 2017 a "Flemish School ca. 1500" Saint Luc painting the Virgin, a tondo estimated at 2,000 to 3,000 Euro.
RKD), and one sold at Bernaerts in Belgium in 2008, which was slightly better painted (also via RKD).
This would mean that the ca. 1500 date is too early, and that a date after 1525 is much more likely (based on the Blondeel) or even after 1550 (if the De Vos is considered relevant as well). The estimate is a bit steep, it really isn't a very attractive work, but it is not the most common theme and in any case quite old, so still an interesting work.