If you are able to send unauthenticated email from TLServer it suggests to me that the simple PRINT #4 "<EMAIL> xxxxx" command should work. Yet you said you are unable to telnet to the SMTP server Ip address, so it is a bit confusing here.
If you go to command prompt of your PC and enter:
C:\> telnet 193.252.22.140 25
Do you get a connection to the server? If the connection is successful the command prompt screen will go blank and you will be put at the first column and first row of the screen. Otherwise Windows will report "Connecting to 192.252.22.150...Could not open connection to the host".
If you are able to successfully connect to the host from a PC on the same network then you should be able to use the <EMAIL> tag to send out the email. I am assuming that the PLC and the PC are connected to the same router and are at the same level for this test to be meaningful. The router must be connected to the Internet provided by freeserve.co.uk.