So, I think I could probably find the errorlog if I could gain access to the filesystem via telnet.
Looking through the version 2.40 firmware from Teks site.
Inside the image is the actual firmware in a file called filesystem.tar.gz
In the directory /etc/init.d is a file called rcS, is the following bit:
# We no longer start up the micro telnet daemon for security reasons.
#
#/usr/share/tek/utelnetd -d
I could modify this to enable telnet, but utelnetd does not exist anywhere in the file system so Tek must have removed it at some point.
Oldest firmware on Teks website is 2.31, but this firmware does not have the telnet daemon either.
If anybody has some older firmware they could take a look at, perhaps it was in earlier versions?

Jay