Indeed, it looks like Chaenomeles.
Herre's an easier recipe, for a syrup, when the fruit ripens.
Half fill a sterilised jar with chopped Chaenomoles quince (discard the seeds, stems, bruises, etc).
Fill up the jar with sugar (and put on the lid tightly...). Put in a dark place for two weeks or so, shaking the jar now and then.
The sugar draws out all the sharp aromatic juice so you end up with a syrup to eat with ice-cream or to make into a hot drink.
This is an Eastern European recipe that I found on the web, then lost again. I hope it hasn't been posted here before.