I honestly don't know the state of the breeding stock on your side of the pond but you would be hard pressed to find a Golden Retriever, German Shepherd or Lab here without some degree of displaysia. If you do find a perfect animal hip wise it will almost certainly throw pups with some degree. It is a sad fact of the way we have bred dogs that problems like these are part and parcel of the pedigree dog. This is what makes me, for one, so angry to be told that I am extreme in my views when I say we should be working towards healthier dogs. If this means losing lines that have been around for over fifty or seventy years so be it!
For Logan - it's not the end of the world, mild displaysia has been overlooked for decades (sorry to drop my sarcasm on your problem Logan, but it's true!) and with medication Lily should have a full and active life.

Try giving cod liver oil in the diet and remember to excersise often during the day, get her up every half hour or so to keep the joint working. Watch her calcium intake, don't over do it, don't stint on fluids and mostly she will tell you when she has had enough. Walks on the leash will help and instead of sitting try a stand position. At her age her weight should really start to come down a few pounds - don't starve her but keep her on the lighter side of normal. It will really help her as she gets older.