No Karen, he has been on the food I described for a long time.
He has almost no treats, one Bonio biscuit per day and tiny end pieces of sandwiches, when we have them. Nothing really.

The vet said his weight is perfect for his size - he is a very BIG dog.
He has been wobbly with his motions ever since we had him as a puppy, never ailing, just normally formed/soft motions, with this periodic diarrhea. It usually lasts about 5 days, then back to "normal".

Our vet said that GS`s are susceptible to tummy troubles and I posted this to get some wider views on it.

Thanks for your reply. We are in Luton.