Hi NJ
I thought the same as you when I saw lamb cheap at our local shop.
I bought one lamb leg and set about cutting off as much meat as possible for pre-cooking and freezing, and I must say, i might a pretty rubbish job of it...........but, I did harness enough meat for 2-3 curries.
Next time I tried, I got better, and better etc, so it IS worth doing. Just as a tip, when you pre-cook lamb meat, it will shrink, so cut larger chunks than you would do for chicken....and it doesn't matter too much if you get bits of fat on the meat as once pre-cooked, you will hardly notice.
GOOD LUCK!
