Then something is not making sense (to me).

.bashrc clearly shows: export
PATH=$PATH:/home/me/bin/context/tex/texmf-linux-64/bin, so does that not
mean that bin can be found via the path? So why does 'context
myfile.tex' not work?

If I run a full path (.
/home/me/bin/context/tex/texmf-linux-64/bin/mtxrun context myfile.tex) I
get the message 'cannot execute binary file' and yet mtxrun is
executable. I checked. Clearly I am making a basic error, but cannot
work out what.

Julian