I was just about to solder a jumper to LMODE to pull it low to be absolutely sure it was set correctly and I went to double check and found this:
https://docs.ghielectronics.com/software/tinyclr/loaders/upgrading-v1-to-v2.html
“Set the down and select pins low on Embedded Master or the LMODE pin low on EMX.”
http://files.ghielectronics.com/downloads/Documents/Manuals/EMX%20User%20Manual.pdf
“General purpose digital I/O is used to choose the access interface for EMX between USB
(Low) or COM1(High or not connected) on startup (refer to EMX access interface section)”
So this might be my problem. I’ve been following the instructions on the first page which says to pull LMODE low for com1 - whereas the manual says to pull it high.
I will test pulling it high.