Federation: using post_delete check causes problems

When deleting a user from my local admin I am presented the error

Traceback (most recent call last):
  ...
  File "/Users/calummackervoy/Documents/Git/sib-app-3.6/startinblox/djangoldp/activities/services.py", line 314, in check_delete_for_backlinks
    targets = _check_instance_for_backlinks(sender, instance)
  File "/Users/calummackervoy/Documents/Git/sib-app-3.6/startinblox/djangoldp/activities/services.py", line 263, in _check_instance_for_backlinks
    value = getattr(instance, field_name, None)
  ...
djangoldp_profile.models.DoesNotExist: Profile matching query does not exist.

Because the associated user profile has already been deleted