Unable to set the correct z-offset for 3dTouch

[DaveJ61]

Hi,

Yesterday, I decided it was time I should update the firmware on my I3 Pro W.
It has been at least a couple of years since I have updated my firmware and I am a little lost.
I believe I have a GT2560a+ board and I have installed the firmware using Arduino 1.01. However, after doing this I am unable to correctly set the z-offset. I have always had trouble doing this and it really is not that complicated.
The firmware was downloaded from here: https://www.geeetech.com/forum/download ... hp?id=4260
I have made sure that the settings are correct to the best of my ability but I am wondering if I have missed something. I am also unable to find the instructions for the firmware configuration, just in case they are incorrect.

I have been trying the various guides abd following them to the letter to set this but it seems to refuse to keep the setting despite saving them.
Could someone please help with this z-offset setting procedure and maybe also provide the link for the firmware config instructions?
Also, how can I check if I have the GT2560a+ board without taking everything apart?