My Mavic Mini drone has an error in the DJI fly app, saying ‘gimbal stuck, however when you turn on the drone and the gimbal moves, it moves perfectly fine on all axis.

Have you tried to calibrate the gimbal?  

Hello, there. Please do not create multiple duplicated threads. We have deleted others.
About your issue,  when a “Gimbal Stuck” warning is shown in the DJI Fly app (error code 40002), the gimbal may be stuck by debris (for example, the aircraft was powered on when it was folded, or the gimbal protector was not removed.). Please check whether there is debris on the gimbal.
If yes, clean off them, restart the aircraft, and calibrate the gimbal. Or please try powering off the aircraft and move the gimbal gently in every angle with your hand, and check whether there is any debris in the gimbal.
If not, power on the aircraft and calibrate the gimbal.
And remove the aircraft’s microSD card and Power on the aircraft and then calibrate the gimbal.

Done all of those things, gimbal still did not work. Disassembled the drone to see the cable (attached image) was snapped, so have ordered a replacement part. Thanks for your help.

djiuser_pE1zn1nbdUHo Posted at 10-7 09:34
Done all of those things, gimbal still did not work. Disassembled the drone to see the cable (attached image) was snapped, so have ordered a replacement part. Thanks for your help.

Thanks for your update. We do not recommend self-repairing. If you need help with your issue later, you can send it back to our service center for repair. Here is the link: https://repair.dji.com/us/repair/index