A 5-year-old who weighs 5 stone? 
Sorry but that sounds very overweight to me. The fact that you say she isn't a skinny minny is a good indication - kids are meant to be skinny! You should be able to see a child's ribs, if you can't and they aren't skinny that's actually a good indication that they're overweight.
I weighed about 5 stone when I was about 10 or 11. I remember this because I remember being weighed for a Maths lesson in Year 6 and that's how much I weighed. Looking at photos of myself from around that time, I was thin but not unhealthily or unusually so. Just in the normal way that kids should be before they hit puberty. And no, I wasn't a midget neither. I can't remember what I weighed I when I was five but it was no doubt significantly less than five stone. Even now as an adult, I still only weigh about just over 8 stone. Well I did at my last pill check last year before getting pregnant but I get weighed at every pill check and my weight always hovers between 8 and 8 and a half stone.
Seriously, how can a five year old weigh five stone but not be overweight?
I think part of the problem is that a lot of parents seem to think that having an overweight child is seen as an attack on their parenting skills. A lot of people seem to think that only bad irresponsible parents have overweight children therefore if their child is overweight and a medical professional points it out to them that automatically means they are attacking their parenting and implying that they are an irresponsible parent. So they would rather stick their head in the sand and ignore the issue.
The thing is, it's not only irresponsible parents who have overweight children. There's a lot of misinformation out there about what a healthy diet actually is. Food that is advertised as healthy often isn't however people buy into it and may think that they are feeding their child a healthy diet but in reality aren't. As I've mentioned before about breakfast cereal, a lot of people think that they are a healthy breakfast, particularly ones that are marketed as being so, such as Special K. In reality they're actually processed shit, low on nutrients and packed full of sugar. Including those so called healthy cereals including Special K. I remember reading somewhere that Special K has more sugar in than Coco Pops. You wouldn't think so by watching the adverts for it. I've mentioned before about reading an article about a mother who was furious her son had been labelled overweight and she went on to say that he has a healthy diet and always has a healthy breakfast of Special K in the morning and never has eggs . I'm sure she thinks that is a healthy breakfast but it's not.
Don't get me started on the fat is evil brigade and eating low fat is the way to go...So they feed their children low fat but high sugar foods instead...but they think this is healthy because they've being led to believe it is.
Then there's the issue of portion control. You could feed your DC's the most healthy diet in the world but if they are eating too much of it they will likely end up overweight. Portions have got bigger so it's easy to overfeed your DC without meaning to. None of this is a reflection of your parenting skills so am not sure why anyone would feel like a bad parent for being told their child was overweight. It's not about you and your feelings anymore. Personally, if a health care provider told me my child was obese I would actually do something about it. I certainly wouldn't stick my fingers in my ears and pretend I know best. Again, it wouldn't be about me and my feelings.
Unfortunately there are a lot of parents who are in denial that their child is overweight.