My gundog takes ages to pick up a dummy!
Gundog training
PETER BLATCH
For a start you can find a smaller dummy that the dog can pick easily and you can also make it more appealing by covering it with rabbit fur or feathers held on by elastic bands.
If the dog continues to take its time then you should gently place the dummy in its mouth and encourage him to carry it.
Done this way you can teach him how to balance it correctly.
A worthwhile way to speed up the retrieve and return is to use an experienced dog to go out at the same time this cant help but sharpen up the little fella.