Missing plaque nearby
William Robertson armorial plaque
(note, it does not seem to have a coat of arms.)
There does not seem to be a SMR entry.

Suggested tags:
historic=memorial
inscription=W.R. 1830
material=stone
memorial=plaque
plaque:type=armorial
wikimedia_commons=File:Rosehill Armorial plaque William Robertson.png

Wikimedia Commons (by OpenStreetMap user b-unicycling):
https://commons.wikimedia.org/wiki/File:Rosehill_Armorial_plaque_William_Robertson.png