Outline of theatre is a little bit suspicious and address of the building is certainly not 2F;4 Rue Hubert Stiernet - Hubert Stiernetstraat.

https://monument.heritage.brussels/fr/buildings/36544

Official address of this puppet theatre is 460A : https://kbopub.economie.fgov.be/kbopub/toonondernemingps.html?ondernemingsnummer=418837090

Social media picture suggest that it's not so big but just a part of the building (otherwise why don't use monumental entrance ? )

Also on the building there is a ktichen maker valcucinebruxelles.be : https://www.mapillary.com/app/?pKey=464162221712149

https://monument.heritage.brussels/medias/buildings/10208169/10208169_0458_P23.jpg

https://valcucinebruxelles.be/wp-content/uploads/2018/05/Cuisine-showroom-Valcucine-Bruxelles-2017-9.jpg

Posbox on 258 suggest there's other occupant too.

way/229579596 : this building doesn't exist anymore (razed) , building levels and outline is guessed from project too.

https://www.mapillary.com/app/?pKey=829018938779905

add amenity=fast_food with access=private ?

https://www.bru4.eu/en/canteen/cafeterias/

It's unusual that a forest in urban zone have no path inside, at least desire. Show some hint here : https://www.mapillary.com/app/?pKey=621710929857974 and on Digitaal Hoogtemodel Vlaanderen II, Skyview factor 0,25 m

Survey needed + change landuse to natural wood (it's not a Managed woodland or tree plantation maintained by human to obtain forest products" here.