I'm using a FT231X for the first time and having a bit of trouble

From the PC side connecting into the FT231X all is good and I can run FT-PROG etc. If I connect realterm I can send in characters and get one of the LEDs to flash (I think the labels are the wrong way around but that is not a big deal), however on the other side if I generate characters at the PIC side I do not get an LED flash and neither do characters appear at the terminal.
I did not need hardware handshake so I left pins 19, 6, 18, 4, 5 & 2 disconnected.
I'm starting to wonder if pin 19 or 6 should not have been left floating?