For those searching for a similar solution, I used the tasmocompiler framework and added the following directives in step 4
#ifndef USE_MATTER_DEVICE
#define USE_MATTER_DEVICE
#endif
#ifndef FIRMWARE_ZBBRDGPRO
#define FIRMWARE_ZBBRDGPRO
#endif
You could equally do this in user_config_override.h if compiling from scratch in platformIO.,
To make life “easy” I first installed the native zigbee bridge pro firmware from the web installer. This pre-populated the berry file system with the files needed to flash the zigbee chip. I do not know whether this is actually required (the files can be loaded manually).
All the best
Justin