Borstal vs Guardhouse

Borstal

name

  • A suburb, formerly a village, in Rochester, Medway borough, Kent, England (OS grid ref TQ7366). 

Guardhouse

name

  • A hamlet near Threlkeld, Eden district, Cumbria, England (OS grid ref NY3325). 

How often have the words Borstal and Guardhouse occurred in a corpus of books? (source: Google Ngram Viewer )