  It is now reasonably clear that disc fragmentation can only operate in the
outer parts of protostellar discs ($r > 50$ au). It is also expected that any
object that forms via disc fragmentation will have an initial mass greater than
that of Jupiter. However, whether or not such a process actually operates, or
can play a significant role in the formation of planetary-mass objects, is
still unclear. We do have a few examples of directly imaged objects that may
have formed in this way, but we have yet to constrain how often disc
fragmentation may actually form such objects. What we want to consider here is
whether or not we can constrain the likely population of planetary-mass objects
formed via disc fragmentation by considering how a population of objects at
large radii ($a > 50$) au - if they do exist - would evolve under perturbations
from more distant stellar companions. We find that there is a specific region
of parameter space to which such objects would be scattered and show that the
known exoplanets in that region have properties more consistent with that of
the bulk exoplanet population, than with having been formed via disc
fragmentation at large radii. Along with the scarcity of directly-imaged
objects at large radii, our results provide a similar, but independent,
constraint on the frequency of objects formed via disc fragmentation.
