Thank you for your support and kind words everyone, that means a lot to me. It's always hard to lose a companion; even though they may be physically gone they are always there by your side in spirit. Cooper is still alive in my memory, my family and friends, and although we can't see or touch him he is still present in a way. He's buried underneath a dog and two rabbit statuettes in our front garden so he can be still part of our lives. I am just glad that my memories of him contain warmth and happiness, and that the end was quick for him and in that the end we did right by him, making the best (and most humane) decision for him, and not just for ourselves.