Season the chicken breasts with salt and pepper and place in a container, fitting the breasts in snugly, this will go into the fridge while the chicken is marinating
Combine lime juice, zest, thyme and olive oil in a small bowl and whisk to mix.
Pour the lime mix over the chicken breasts ensuring the chicken breasts are coated. Marinate in the fridge for 2-3 hours, turning the chicken a few times.
Remove the chicken from the marinade and place on a hot BBQ grill, grill for 7-10 minutes and then using tongs turn over the chicken breasts and grill for a further 7-10 minutes or until it is cooked through. When you Insert a sharp knife in the thickest part of the chicken breast and the juices run clear then it is cooked through.
Leave the chicken to rest for 5 minutes while you place the lime slices on the hot grill to char.
Place lime slices on top of chicken and serve with a salad