I chose 12 as I am a 12 on the bottom half (12s are a little bit big for me but I'm not small enough to wedge my hips and thighs into a 10!). I am usually a 10 on the top though.
8/10 in 'normal' clothes (jeans etc) but for some reason have to buy bigger size in jods (28-30 waist), which I think is a 14-16? Very odd, must have a weird shape for jods, and they always bag around my knees and calves!