Advice needed re: food for puppy

[cyclingwife]

Hi,
My Dpup is a labrador 11 weeks old. She has been fed the same food as her breeder put her on (Eukanuba puppy). She had diarrhoea two weeks ago which we put down to either treats or finding something dodgy to eat in garden (she's on a lead). We put her on a bland diet of cooked chicken and rice. Then after a few days all good so we went back to her dry food. But again diarrhoea returned.
She was at the vets at the weekend for her last jabs and the vet said no temperature, diarrhoea was likely to be just sensitive puppy, as she was growing well (put on 3kg in 2.5 weeks) and was healthy other than the diarrhoea. She's fine in herself, alert and vet had no worries.

As her diarrhoea means we're taking her out every hour and she's having accidents inside at night I'm not sure whether to stop her main food and change to a different food for sensitive tummies? Or maybe grain free?
There is such a range of dog food out there, I have no idea where to start, especially as changing food could make her tummy sensitive. I'd be grateful for any advice.
Thanks

Yes @talia66 that's what we're doing, trial and error. We know that cooked chicken and rice improves her stomach. Treats do not.

@Girlintheframe thanks, my husband has ordered a trial puppy bag from millie wolfheart, to introduce in a small amount with the chicken and rice. Just for the time being whilst we do some proper research and then speak to vet.

@GetawayfromthatWelshtart thank you so much for your kind message. Mumsnet is playing up and I can't reply directly. But very much appreciated , you are totally correct

Update:
Dpup's tummy probs resolved with chicken and rice, quality dog food on order and hoping to introduce slowly. Thanks so much to everyonewith supportive messages. It is lovely to hear other's shared stories.

If it's any consolation, our pup had regular tummy issues until she was around 6 months, and she still gets the odd bout at 13 months. She's quite anxious so it doesn't take much, and she's a little so and so for eating things she shouldn't.

We always go straight to chicken and rice, Pro-Kolin probiotic paste (from Amazon, it's half the price the vet charges) and if no better in 3 days, then we trot off to the vet.