Helllo..
The problem: The camera takes barely 40 pics with fully charged batteries.
Solution I thought was: send it back to the Canon repairs and they should work out what the problem is. I had written a note + called them when I sent the camera. But, they sent it back to me with a note "no fault found".
Called them up again - response - "check your batteries"

. well I know I am not an expert but I'm not that bad!
What next? Any suggestions?!
The batteries work perfectly well. I can take more than 600 pics with my Fuji S5600 with the same set.