Preheat the slow cooker on high for 20 mins
Brush bottom of slow cooker with oil
Untie pork shoulder and trim fat and skin (Keep for making some pork cracking)
Heat oil in frying pan and fry onion and garlic until soft
Mix other ingredients in a jug
Place the pork shoulder in the slow cooker
Add garlic and onions
Pour over sauce
Cover with lid and cook for 7 hours or until tender.
Shred the pork and leave to stand for ten mins in the cooking juices.
Serve on rolls with coleslaw.