Hello, the spoon is from Copenhagen, the assayer is, like you wrote Christopher Fabritius (1749 -1787) and the makers mark is the mark of Jean Pierre Stoundre (Stunder), ca. 1763-1822 (Bøje Københaven, p. 197). J. P. Stoundre is quite young, may be to young to be assayed by Christopher Fabritius (?)...