OK, another day, another app
As I originally mentioned, the Bracket part of my test app was a bit flaky but as another forum member wanted just the bracket part, I've made a dedicated one.
Usual story, activate the Wifi on your Panasonic camera and select Connect.
Choose the base shutter speed with the Shutter button.
The choose the number of plus and minus steps that you want with the sliders.
These are 1/3rd steps so its 6 stops in either direction.
Depending on your particular Panasonic camera, you may have to activate electronic shutter to get the upper values if you've got a high base speed and have a number of + steps.
If you don't activate electronic shutter then it will just go as high as it can with the mechanical shutter and then repeat the same frames after that.
When you are all set up, press the Bracket button and it will begin executing the commands, beginning with your base frame and then doing the over and unders that you have set.
To prevent overloading the Wifi and to take into account slower FPS cameras there is a delay built in between frames.
Download link is here