chippy dont get a German Shepherd unless you have the time and patience to put in to training and exercise. They are smart dogs who need stimulation - not lying around the fire until you can fit them in.
And I am not sure what planet your husband is on, I assume he wants a 'status' dog? A big scary husky, or an even bigger scarier GSD?
There is not a rescue in the world that would give your family an ex working dog, especially not a police dog. That is an accident waiting to happen.
I have had dogs all my life, labs, JRT and mostly GSDs. I have had children while trying to train and exercise a puppy GSD, it isnt easy. Fabulous family dogs if brought up in the right environment, destructive, nasty and an enormous amount of hard work if taking on someone elses problems. I am the voice of experience here.
Please think long and hard about how much time, love, care and attention you can give any dog, not to mention expense. Big dogs cost more for everything, from collars/leads, food, vet fees, insurance, even their bloody beds. 