I have designed the cradle for use with an iPhone 12 Pro and this magsafe charger available on Amazon UK:
Note: If you want to use your own charger you will need to modify the design. Feel free to share any new designs via additional print plates.
The holder comes in 3 parts. Once printed, simply glue the cradle into the desired position in front of the rectangular hole on the lid as shown below.
Pass the magsafe charging cable through the hole and feed any excess cable into the base through the hole behind the cradle.