I am currently laying 100sqm of Porcelain 20mmx900mmx600mm at home, quite a challenge as a self builder., not a professional.
Mostly level, some walling and steps.
If this was my problem I would try core drilling through the lower rectangular tiles at the base of the wall and continue through the brick retaining wall.
If the tiles break, remove them, drill retaining wall, clean hole through new tile and fix.
It looks very smart in the photo.