These are essentially 100% soft fondant, with the obvious exception of the coconut coating.
The product that I remember from childhood and made by several major confectionery companies, as well as more recently purchased from and made by a small local factory, used fondant for the stalk but a cocoa-coloured marshmallow for the head of the mushroom. Consequently, they were less sweet than are these and provided a mixture of textures, from the pillow-soft marshmallow and the slightly harder fondant, and then the chewy coconut.
These were chosen by another family member as the local factory closed a few years ago after the death of the owner and confectioner and a comparable product had not be seen for some time. I found these to be just too sweet, lacking in any perceivable flavour other than from the coconut, and possessing a sameness of texture. You really do not want to eat any more than two or three. The 1Kg bag was therefore just too much! As with another Taverner's product purchased at the same time, these were a major disappointment and it is an experience that is likely never to again be repeated.