I agree with others that raw feeding would be the answer, but also understand it isn't possible for everyone to do. I have done both raw and kibble feeding over the years, mainly because I don't have large enough freezer to store enough to feed two (used to be three) large dogs and also because I went from having a really friendly, generous butcher, to not being able to source bones easily when we moved house.
If you can't do raw I would look into what's in the food that she could be reacting to. Many dogs react to grain, some just wheat, but some almost any kind of grain, including rice. Then have a look at the Which Dog Food? website and see which foods exclude that ingredient.
I'd also ban all treats and chews. Most of them are just junk food for dogs and some contain all manner of nasty ingredients. For training and treats etc, I would go for fresh cooked chicken in the first instance - as long as you're sure she can tolerate chicken - some dogs can't.
If her poo has always been that bad, I would be asking the vet for a stool sample to check for the most obvious causes (this will cost about £100 though) and putting her on some over the counter canine priobiotics for a while to help improve her gut flora. Long-term loose stools are likely to mean she has unbalanced gut flora and the probiotics will help her to generate more of the friendly bacteria.
My pup (a rescue Lurcher, also 7 months) came to us with a nasty campylobacter infection and whilst the antibiotics killed the infection, I swear it was probiotics that made the biggest difference to him. He went from explosive diarrhoea to normal poos within the first 24 hours of starting the probiotics. Prior to that he couldn't absorb any nutrients from his food, as it was rushing straight through him and he was emaciated as a result. He started to gain weight almost as soon as he started the priobiotics.
Our vet gave us Canikur at the first appointment, but I sourced it online here for half the price the vet charged. I'd recommend getting the largest size for a Goldie as they get through it quite quickly. Dogs love the stuff, as it's palatable, so much so that I was able to use my pups dose to plug the top of his puppy kong when he was younger. He still gets excited if he sees the syringe. 
I always keep a syringe of it in these days, as it sorts digestive upsets really quickly.
When our boy was ill, we stopped all kibble and fed only fresh cooked chicken, plus probiotics for a couple of weeks. We only started to introduce kibble once he had had totally normal poos for a week and then really slowly - as in a couple of nuggets per meal to start with, increasing it very slowl from there over a couple of weeks. Once he could tolerate half a feed of kibble, we switched him completely over and he's been fine ever since.
My dogs are on Canagan, which has a high quality protein source and is grain free. It's expensive, but worth it, as it suits them both and they're in great condition on it.