Can anyone help identify the artist and subject matter

It seems to me it is a castle scene from the Scottish Plains and the artist's last name is Stuart. There are a lot of Stuarts listed online. Could really use some help with this one from an expert on here. Thanks!

 

Dude, there is no such thing as the Scottish Plains. I think you mean the Lowlands, which would be correct.
The hills in the background are the Eildon Hills, or Eildon Hill, in the Scottish Borders region, south of Edinburgh. Technically speaking one hill with three peaks.

The name looks like STD Wart? I can't see Stuart. Or Stewart. I don't think the name is that important, it is an amateur painting of an attractive subject.

I have seen the building but can't recall which one it is. There are some famous Medieval abbeys and tower houses in the Scottish Borders.

Scott's View, with Eildon Hill(s) seen from the other side, this was the favourite view of Sir Walter Scott:

 

Here is a list of places in the Scottish Borders:
https://en.wikipedia.org/wiki/List_of_places_in_the_Scottish_Borders

 

Thank you. Quite informative!

 

Research indicates that Stowart is included in a directory of Irish individuals. I am absolutely not an art person other than to admire, but this looks like a hobbyist painting to me. Thus Stowart might not be included in any list of artists but may have been to Scotland to paint.