Thanks all, I have decided not to give him any more milk, I have had a read around the net and it seems it's 'nice, but not necessary'. Really, I would prefer to keep things simple, just Nutriment & water, plus grain free treats and training rewards. He is really good, eats all his food and, at present, shows no interest in human food, I would like it to stay that way.
The poor cat is most put out about this noisy puppy arriving, so I will let him have the goat's milk instead!