now there are 2 objects: 'chapelle du Saint Sang' and Église Notre-Dame-et-Saint-Sang.

The correct name is "Chapelle du Saint-Sang" (according to Wikipedia, it could also be "Chapelle du Saint-Sang de Miracle")
https://nl.wikipedia.org/wiki/Bois-Seigneur-Isaac

And then there's égliseinfo, they say the Chapelle is a Basilica with name "Basilique Notre-Dame de Grâce et de Consolation et du Saint Sang" (Grande chapelle)