
Welcome to the board. I am glad yopu have joined the board as we said perhaps we can help you further.
Regarding litters, most flatcoat breeders do not have a litter from their bitch before she is 3 years old and then the Society ethics say ideally no more than 3 litters during her lifetime. Obviously a litter at this young age will not kill her unless you are unlucky, and I have known biches die while whelping. Owning a dog and a bitch is a huge responsibility, and great care should be taken to ensure that they do not get toegther again, as they have this time. Perhaps you should consider this a lesson well learnt and build into your househld the means of not allowing them to run together.
It is good to hear both the hips and eyes of your dog and bitch are tested, this is an age when puppy buyers can and often will take a breeder to court if they think they have bought a puppy that is not what they expect. There have been cases in other breeds where the breeder had not had his/her stock eye tested or hip scored and the buyers puppy had ended up affected. The courts decided that because the breeder had not had the animals tested prior to breeding they were indeed liable to return the puppy buyers money, plus they had fines and court costs to pay. A few years ago a GSD breder was fined £3,000! Plus had costs and the buyers money returned on top of that.
I would advise you to join the breed Society especially if it is your ambition to breed flatcoats, and take on board the code of ethics most of try to abide by. The welfare of the breed MUST always be put first and foremost. Perhaps you might join the flatcoats@yahoogroups.com message board, where there are many very experienced flatcoated retriever breeders all willing to listen and offer an opinion. As you point out, we all have differing opinions, but the code of ethics are a good guide to work by. It can be confusing, especially when you first start out, so do it right and listen to those with the experience and knowledge, take your time, plan your breeding policies and take your time to learn as much about the breed as possible prior to the next litter.
One final thought, we can appreciate one mistake, but after that it is hard to believe, and certainly if you are going to be a good responsible breeder, you won't make that mistake again.
Good luck with your litter, I hope you'll let us know how you get on with it, we are genuinely interested, and do want to help.