Loved this.
I used half plain yoghurt, and half mayo (not miracle whip!).
I left out the celery and onion, and upped the paprika and added a splash of cayenne.
I did put some pickle relish in.
I leave people to add their own salt, because it is personal preference, but I did put pepper in.
An absolute must is good Dijon mustard - don't be shy with it.
Lastly, I roasted the potatos, which was a hit!