I find British Lamb to be the best available and shall always make that my go to option given the choice.
Lamb, a young sheep under 12 months of age which does not have any permanent incisor teeth in wear. (From July 1, 2019, the Australian definition is “an ovine animal that: (a) is under 12 months of age; or (b) does not have any permanent incisor teeth in wear. The New Zealand definition also allows “0 incisors in wear”.
Download the .pdf from this link: Roasted Lamb Shoulder