I don't think that these pieces are legal. It might be possible that the owner of that wall has a positive attitude to graffiti. The spot is painted frequently with new pieces; so you possibly will find it changed.
In 2013 I started with a new hobby. In the beginning it was difficult to get reliable information how to find streetart in public space. In 2016, I had the idea of sharing my information with other street art enthusiasts and started my blog “Streetartwalks”. When I found out about this new street art community at the beginning of 2018, I was immediately on board.