Bought same brand but bought for 'mini' not large breed. Pup is 10 weeks. OK to use or do I need to change it? Bearing in mind I would almost guarantee that nobody in the pet shop will speak English and I will struggle to explain!
It would be fine if it were the same make, but its not great to change makes overnight as it can give them the shits. Which really is more of an inconvenience for you as you have to pick it up. If you want to change - do it gradually over a few days.