Storage Problem

I bought this for my daughter puzzle of 3½ years fan of Fireman Sam.
At first she loves but regrets that Sam is on one of the 4 puzzles. The parts are lightweight carton as an adult puzzle, and therefore not necessarily very strong. The fact that it makes these cars a little difficult puzzles in particular to understand what each part.

Positives
The storage box with a small handle is amusante.Les 4 puzzles have a growing number of parts and are scalable.
Bought 12 euros, so about 3 euros puzzle, still reasonable but could be cheaper given the quality of the cardboard pieces.

Negative points
There is no storage system to separate puzzles, it was not even planned a small design on the back of the pieces to easily separate puzzles. Result they are all mixed in the box, which is larger than necessary to contain and is therefore losing storage space.

Finally, the product is as described, 4 puzzles from Fireman Sam, basic quality with a storage system to be reviewed.