Right, so about six hours later, I’ve discovered a bunch of random stuff I didn’t know before, but more importantly, I think the answer to this problem lies in:
grep -i framebuffer /usr/lib/kernel/config*
For the particular version I’m running at the moment, part of what this returns is:
# CONFIG_FRAMEBUFFER_CONSOLE_ROTATION is not set.
Based on that, I’m presuming this defaults to being disabled. According to other posts:
For fbcon commands to work, the kernel needs to be compiled with:
CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y
It’s currently a tad beyond me to understand how to recompile my own version of the Clear Linux 5.3.5-847.native kernel, so unless someone can help with that, I think this now stalls as being dependent on the dev team to enable this parameter by default.
Cheers