Remove any giblets etc. from the cavity of the chicken, sometimes in a small bag.
Stuff chicken with 1 sprig of rosemary, 1 lemon (quartered) and 4 cloves garlic.
Season all sides of the chicken with salt and pepper.
Remove both ends of a lemon, cut in half to create very thick slices.
Line the bottom of the slow cooker with 4 lemon slices, 4 whole garlic cloves and a sprig of rosemary.
Put the chicken in the slow cooker.
Cut 2 garlic cloves in half and put all four pieces on top of the chicken along with the 2 remaining lemon slices.
Garnish with 1-2 more sprigs of rosemary. Put the lid on the slow cooker and set to high for 4 hours.
Place cooked chicken under the grill (broil) for 10 minutes to crisp the skin (optional).
Allow chicken to rest for 10 minutes before carving and serving. Leftover juices in the slow cooker are mostly lemon juice with a bit of chicken fat and can be used sparingly as a strongly flavoured sauce.