Thanks for the help. Unfortunately I can't go with software, this thing also does dimming and I need to use hardware serial so I can carry on with my dimming routine at the same time. I do have a spare i/o so unless anyone has any other suggestions, I will just have to solder a jump wire on the chip itself, seen as I can't get to the underside of the PCB any more. One thing that the chip does allow is for you to disable the TX pin by setting it as an input, but unfortunately I need it as a standard output.

Matthew