Off the top of my head the following information may interest the OP.
The box at Kirkby Stephen was replaced in the 1970's with a standard BR design.
The box at Blea Moor is also not the original one which was built to a Midland Railway design and was on the opposite side of the line. The current one was built in the 1940's when loops were installed at Blea Moor and was built to a standard LMS design.
There were originally many more boxes on the S & C. From what I can remember those that closed in the 1980's included Dent, Ais Gill, Settle, and Horton. Dent, Ais Gill and Settle were planned closures; Horton was actually "switched out" when it suffered fire damage and was consequently demolished.
Blea Moor wasn't the only remote box on the line. Mallerstang box could only be reached via a footpath across several fields and Dent Head signal box was in a pretty remote spot too.
Although long since closed the signal boxes at Settle and Armathwaite still survive. The box that was at Selside is now falling to bits at Carnforth and I'm pretty certain the box that was at Ais Gill is now at Butterley.
When the line was busy with coal traffic all the boxes were manned over a 24 hour period but I wonder if this has now changed following the loss of all the coal traffic. During the 1980's Garsdale was "switched out" and was only brought back into use for WCML diversions.
Kind regards,
Richmond Commuter.