Brett,
Did some more testing, took the UART upto 460kbps and was getting 160kbps out of the unit, performance seems to level out here (not a huge difference between setting the UART to 230 or 460) so either this is where the limit is practically or there is a bottle neck either in the app, BC127 or the UART link itself.
As a rule anyone driving data rates over 115200 goes USB because serial links start to get unreliable beyond this.
Regards
Matt