In a medium bowl, combine the broccoli, celery, and red onion. (Do not add the walnuts, raisins and bacon until it is ready to serve) In a small bowl, whisk together the vinegar, honey and mayonnaise. Pour over broccoli mixture, and toss until well mixed. Refrigerate for at least two hours.
Before serving, toss in the crumbled bacon, raisins and walnuts.