Halve potatoes if they are large, and place in slow cooker pot.
Make incisions in roast and press in garlic and rosemary. Place any loose rosemary leaves in pot.
Place roast on top of potatoes.
Add stock and bay leaves to bottom of pot. Roast should sit just above the liquids.
Cook on high for 4-6 hours until meat is cooked. Wrap roast in foil to rest for 10 minutes before carving.