I've managed to get some help elsewhere on this issue, thought I'd post here in case anyone else has the same problem.
Echo the PATH from MATLAB itself:
cmd=['echo $PATH']; system(cmd);
In my case this gave:
/usr/bin:/bin:/usr/sbin:/sbin
and does not include the usr/local/bin where my binaries are stored. Therefor this needs to be added via
setenv('PATH', [getenv('PATH'),':','/usr/local/bin']);
which now gives:
cmd=['echo $PATH']; system(cmd);
/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin
If you start Matlab from a terminal the PATH is different, and contains usr/local/bin, but starting it the "usual" way through Applications causes a different PATH. No idea why!
Jim