To everyone that has recommended Levi's Demi Curve jeans - THANKYOUSOMUCH!
Usually have to buy a 14-16 and cope with huge flappy waistband. Bought a pair of Demi Curve skinnies with a 31" waist (not a huge difference but Levi's are usually very small on me) and it's like I've found the Holy Grail.
Amazing fit, no unflattering crotch tightness,fit my large bum and hips like a glove and the waist is not flappy (I do need a belt but next pair will be a 30". I bought these from Ebay to check if they were right for me before shelling out full price). Very happy indeed - can now wear normal tops with jeans instead of tops down to my knees to cover either excess material or muffin top. 