Peel and chop the potatoes and then simmer them until the potatoes are soft enough to easily pierce with a fork without breaking apart.
Add the potatoes and cooked macaroni to a large mixing bowl and toss with vinegar while still warm.
Allow the potatoes to cool. Add the mayonnaise. Fold the potatoes, macaroni and mayonnaise just until combined.
Add the garlic, peas, carrots, sweet relish, red onion, celery, salt and pepper. Again, gently fold to combine. Store in the fridge to chill.