Looking at imagery, this looks to be apartments.

There is fire station mapped on the nearby London Road:
https://www.openstreetmap.org/#map=19/51.73767/-0.31221

https://www.hertfordshire.gov.uk/services/fire-and-rescue/fire-station-locations/st-albans-fire-station.aspx

I'm assuming this note was dropped in the wrong location and closing it.