Hello tillydimond and welcome to the forum!
How they do worry us at times, these pooches! Isn't it frustrating when a product is no longer stocked especially a food that has previously been eaten without causing issues. If this is Nature's Way puppy food and your dog has done well on it then it's as well to be aware that that particular food does not have any maize (corn) or wheat in it, has 1 protein, namely chicken and is free from soya, dairy, artificial additives and with no added salt or sugar.
With this in mind and if your pup has been well on that food it may be prudent to take a look at the allaboutdogfood dog food directory which is here:https://www.allaboutdogfood.co.uk/the-dog-food-directory
and use the filter called "Avoid ingredients" to tick the box "all red ingredients
" which will then avoid all foods which have any (or a combination of) "Artificial additives", "Added sugars", "Added salt", "Soya", "Dairy products", "Wheat", "Maize".
If you also use the filters to add your pup's age (in the "Dog's Age" drop down menu box) of "7 months" and your dog's breed of "Labrador Retriever" and then press on the green "GO" box, there will be several results of suggested foods. You can filter these further by "Highest Rating" or "Lowest Cost", etc using the "Ranked by" filter.
If you might prefer to remain with 1 protein (eg chicken) and/or you suspect there may be a particular ingredient which may not be agreeing with your dog, then you can also tick any of the other boxes with named ingredients that you wish to also avoid feeding.