Winning Edge Gold, a 20kg dry dog food aimed at working and highly active dogs rather than the pet market.
Gold is the standard formula in the range; Platinum is the higher specification. Match the formula to the dog's actual workload — a high-energy food fed to a lightly exercised dog puts weight on quickly, and that is the most common way an owner ends up blaming the food.
Check the guaranteed analysis on the listing images before switching, and introduce any new food over 7-10 days.
Freight note: 20kg bags are heavy freight. If you run several dogs, ordering more than one bag at a time is normally the cheaper way to buy.