Navman Mivuedrive FHD

Is this a place to ask about a GPS unit? It appears that the battery in my Navman MivueDrive FHD is cactus. The Navman agents regard it as non replaceable, but also tell me that they are aware that some people have replaced the battery, and suggested that someone like battery world might help me. Question is, how do I open the unit; there are no screws visible in the casing.

No specific knowledge of the navman. But you need to work out where it would open, it may be just clipped together.
Try to slip a thin blade into the joint and lever gently.

Good luck.

Have you searched the web? You might find a video showing how it's done.