If the MiR doesn't automatically connect to “Heron Mobile Wifi 5G”, you can make it connect manually.
First, make sure that “Heron Mobile Wifi 5G” is actually started, and visible.
Connect to MiR's own wifi “MiR_s1319”.
Open a web browser and go to
http://mir.com
This should get you to the MiR web interface.
From there visit “system” → “settings” → “wifi”.
There you should see “Heron Mobile Wifi 5G”.
Press “connect”.
Simon wrote a script that can attach mir/base_link to map
It's in heron_ws/src/robots/heron_robot/heron_robot/scripts
You can run it through rosrun heron_robot map_tf.py