That was the problem yes, except mine’s an Uno.
… NL & CR works! +++ now lists available commands and all is beautifully intuitive 
Wonderful work.
So the program checks for data in eeprom, and if nothing is found default values are used defined in the sketch… Hence out of the box functionality with emonTx?.. With my uno/TxShield the eeprom values were ‘nan’ but their use was attempted regardless, meaning I had to write to the eeprom to get any usable values transmitted. No big deal.
I think this may specific to the Uno, I’ve got the official R3 with no change to the EEPROM before adding this sketch. I don’t know.
I have a second official uno, blank also, which I could test with now I’m more familiar with the setup.