Thats the best place to take him.Which wormer did you use and what dosage did you give him? Was that the 1st time you've given him breast of lamb, and did you strip the meat from the bone or was the bone attached, as lamb can be very greasy and if the bones were attached it could actually splinter his guts. I would just stick to his complete meal and just give him the odd knuckle bone to chew on now and again.
Hope everything goes well has he's a beautiful looking puppy, and a credit to you.