There's a Belgian connection here, so why not (also) look at what publications here mention Henri Leenaerts. He was a 37-year old former insurance agent and swimming instructor from Brussels.
Orders were to organize an intelligence gathering group.
Landing point for the Lysander was to be at/near Momignies, a small village just inside Belgium (in the south of Hainaut province) and roughly between St Quentin (FR) and Charleroi (BE).
Some texts refer to Flak near Boulogne for cause of loss of Lysander.
Much of above can be read here as well:
https://beforetempsford.org.uk/17-august-1940/
Regards,
Leendert