\Android\data\com.tomtom.gplay.navapp\files\data\maps\xx <----Each one is numbered.
The folder \Android\data\com.tomtom.gplay.navapp\
Could be on your phone memory
or on your External SD Card.
Mine is on my External SD Card.
Benelux = 28
I would copy the whole folder over.
Do not know it that will work or not.
Might be easier to copy the complete folder \com.tomtom.gplay.navapp over to the other phone.
As I have not tried this it might not work.