Set the slow cooker to low.
Combine meatball ingredients, except oil, in a bowl. Shape mixture into large balls (about the size of golf balls).
Heat oil in a large frying pan and brown the meatballs.
Remove from the pan with a slotted spoon (or drain on kitchen paper).
Add prepared carrots and courgettes to the slow cooker bowl and place meatballs on top.
Combine remaining ingredients to make the sauce. Pour over meatballs.
Cook on low for 6-8 hours.
Serve with freshly cooked fettuccine.