I have never come across these yummy mummy types and I live in an area where you might expect to.
I have come across two types of semi yummies the first set do everything properly breastfeed for as long as possible, blw, handcook everything, arrange really stimulating playdates but they look far too knackered to qualify as a proper yummy mummy.
Then there are the other semi yummies - latest designer clothes, immaculate make up, gym-honed bodies but they are so busy maintaining themselves that they are a bit sloppier with the kids, fruit shoots, too many dvds always forget it is show and tell etc.
Most mums I meet are totally normal (just like me! ). We try to get our kids to eat healthy and take an active part in their education but we allow chocolate if it keeps them quiet and we do slip the odd tesco finest ready meal in our shopping basket. We might blow dry our hair and wear lip gloss to go to the school gates but our pubes are poking out of our mismatched underwear because we don't have time to be that well groomed!
Just lighten up everyone and stop comparing yourselves to others. No one is perfect, if someone makes you feel inadequate think about why that might be? The problem is more likely to be YOUR perception of YOU than it is to do with them.