Edwina Dyson clearly made life hell for you. But as much as you remember her, she might not remember Eleanor Smyth. Assuming she's grown up (as most people do), reconciling her maturity now with the identity of the bully she once was will be difficult, and she may well have blocked out some of the details in order to move on with her life.
Bullying is awful, and as you know, can lead to some very tragic and permanent consequences. However, in this country, we believe in rehabilitation not punishment, which means if people do bad things, we hope that they will understand what they did was wrong, pay a penance and then be reintegrated into normal society again (unless they're a very real danger to others).
Most bullies don't need to be locked up for the rest of their lives. Most of them are dealing with their own pain and/or haven't matured as fast as they're supposed to, and just aren't processing increasingly complicated emotions properly. It's not right that they've taken out their circumstances on other children, but the blame really lies with the adults who haven't identified the bully and taken steps to stop them harming others.
There's a reason we don't let children live independently - they're not yet capable of adulting. Adults are supposed to notice when they're behaving badly and guide them into acceptable behaviour or, in the worst case scenario, lock them up if need be. You were failed by your teachers and Edwina's guardians, but so was she. She shouldn't have been allowed to have been that awful.
Most things that make people bully others are things that can be dealt with, i.e. most bullies can be reformed and released back into human company.
If someone was a little shit at school and it's only a year later, chances are, they're probably still a little shit. But if you're now head of finance, you've got to be, what, at least in your 30s if not older? That's enough time for Edwina Dyson to have got her life together. She's married now - which suggests she was able to redeem herself enough for at least one person to see some good in her. It's very, very unlikely Edwina Craig-Dyson is the same horrid girl you remember.
It's only natural to want to somehow shame or embarrass Edwina, because you have no idea what she did to atone, if anything. I mean, she's probably a better human now, who has had to confront what a little shit she was, and make her peace with that, but you don't know for sure, and the younger you hasn't forgotten the hurt. But actually following through with that desire to lash out isn't the right thing to do, and I think you know that.
If you attempt to use your success now to belittle Edwina, you're showing that you haven't moved on from your childhood. I think it will undermine who you are now, and the great things you've achieved. Bad idea.
The advice to rise above is difficult to swallow, but it's all I have for you. You've made something out of your life, you really have - tearing down people who hurt you on the way to get here isn't going to make your life now any better, because it's already pretty damn good.
Be the bigger person.