The corridor is low and narrow placing you below minimum safe altitude
The words "low level" and "route" do tend to make most pilots aware of that.
As far as "minimum safe altitude" goes, that term doesn't exist under ICAO. Minimum Sector Altitude (if that's what you actually meant to refer to), refers to IFR and this is exclusively a VFR route.
As a "notified route" the 1,000 ft rule doesn't apply either.
