Update on the information below

It may be best to delete the monitoring stage all together as monitoring is possible via headphones using the UMC 40 interface. The complete stream is also sent via the UMC 4040 to my Mackie Audio interface

the routing using Jack, the UMD 404 and the hardware monitor mixer is also an awful mess.

To cut a long story short to hear a realistic mix of what is broadcast via ice cast and what is heard in the kiosk (without accommodating the physical acoustic) use headphones to monitor channel 1 only on the yamaha mixer and effect all mixing using the Akai APC mini. The routing is confused because of the proliferation of actual and virtual inputs and outputs in

PD
Jack
UMC 404
Yamaha Mixer

But critically in Jack all pure data outputs are routed to playback 1 of the UMC 404 presumably I did this to accommodate the live broadcasts