Turn your slow cooker to low.
Heat a frying pan to moderate-high heat on the stove-top and add half the olive oil.
Season the lamb with salt and pepper and brown, turning often to brown all sides.
Set lamb aside.
Add remaining measure of oil to the fry pan and add the onions and garlic, stirring for about 15 seconds, or until fragrant.
Immediately add the wine, and boil for 1 minute.
Add the beef stock, Worcestershire sauce, mustard, honey and half the chopped mint and bring to a gentle simmer then remove from the heat.
Transfer lamb to the slow cooker and pour the sauce over it.
Cover with the lid and cook on low for 8 hours or high for approx 4 hours, or until the meat tender and easily pulled from the bone.
Approx 2 hours before the end of cooking add the baby carrots and stir through the sauce.