I would contact the secretary of the GSD Breed Council, if you do a search you should find their website. She lives in Essex but don't want to put her no up here (in fact will pm it to you). They have a list of approved breeders which has far stricter conditions than the KC one. It is difficult to advise regarding bloodlines cos it depends on what type you are looking. ALWAYS make sure both parents have been hip scored and have low scores, I would personally not consider anything with a score above high teens. If you have any bloodlines /breeders in mind if you want to pm me I will tell you if I know of them. Good choice on picking the best breed there is (can you tel I am biased!)
Sorry computer out of order, having a quick catch up on friends. I'vegot 3 shepherds, 12 year old, 10 year old and 7 year old,so as you can probably work out not breeding at the mo! They are mainly german breeding, Ibred my first litter nearly 30 years ago but sadly the 7 year old is the last of my line and she had bad hips so can't be bred from. I'm hoping to have a pup next year from a friend who had his first bitch from me so will have the line back. If you just want a companion/pet I would stay away from the really strong working lines, they can be hard work. Hope you find theright dog, if I can beof help in any way please ask though I am a bit out of touch nowadays.