A white and grey gathered frock with cotton satin and net would be both elegant and stylish! Here's how you could envision such a design:

1. Color Combination: White and grey create a sophisticated and versatile palette. The white could be the predominant color, with grey accents or vice versa, depending on your preference. Grey could be used for detailing, trimmings, or as an accent color in the print.

2. Fabric Choice: Cotton satin would provide a soft and smooth texture, making it comfortable for kids to wear. Net fabric can be used for overlay or detailing, adding a touch of delicacy and elegance to the frock.

3. Gathered Design: A gathered waistline adds volume and creates a flattering silhouette. You could incorporate gathers at the waistline or use a gathered skirt for a fuller look.

4. Print or Embellishments: Depending on the aesthetic you're aiming for, you could choose a subtle print in shades of white and grey for a minimalist look. Alternatively, you could add embellishments like lace, embroidery, or sequins to enhance the elegance of the frock.

5. Details: Consider adding delicate details such as lace trims, satin ribbons, or fabric bows to enhance the overall design and make the frock even more charming.

Overall, a white and grey gathered frock with cotton satin and net would be a chic and sophisticated choice for kids, perfect for special occasions or formal events.