Hi George,
Were you injured by the bone? This may not be a consumer law problem. However, you can try contacting the
Department of Fair Trading to enquire. It appears to be more of a personal injury issue, falling under general law.
If you were seriously injured because of the bone and incurred substantial medical expenses, there may be recourse there. However, if you just found a bone, but did not suffer any damages, it may not be worth pursuing at law. The costs, time and expenses would be substantial compared to what you would likely receive if you were to win. And the chance of succeeding would be low. Again, this will depend on the circumstances of your situation.
Did you bring it up with the restaurant? How did they respond?