I was debating whether to post as a) I'm a rubbish mumsnetter and rarely come on here and b) everyone's path is different and I'm not sure how helpful sharing mine will be. But after reading through the thread I've had a few aha moments and I think writing my thoughts down may help me clarify where I'm at.
The bit about the 'animal' brain and the 'higher' brain really resonated with me. Except mine isn't an animal, it's the stoppy, selfish, rebellious brat side of me that I should have outgrown long ago but insists on hanging around. So first things first, I'm going to focus on controlling the brat and ignoring her as she has no positive contribution to make to my life.
Secondly, whilst I love the idea of eating mindfully (I read and really engaged with Paul McKenna's book 'I can make you thin' - awful title, fabulous book - a number of years ago) I realised that I approach this the same way as a diet, ie. "tomorrow I will start eating mindfully and will do this, this and this". My brat brain recognises this as diet mentality and immediately starts to persuade me to rebel against it. I'm going to think about this further and consider how to overcome this mindset.
I think there's a lot of fat-shaming happening at the moment, cost of obesity to the NHS etc. Whilst I'm not dismissing this, I don't think this approach is helpful. According to my BMI I'm obese, yet I don't drink, I don't smoke and I'm active and I haven't visited my doctors for anything other than mastitis in the last 20 odd years, so I'm not costing the NHS anything. The post upthread about how obese people can be as healthy as 'normal' weight people was really helpful, thank you. I'm not going to be made to feel guilty about my weight anymore.
Finally, I think the key (for me) lies in body positivity. Really learning to love and accept my body at the weight I am now and also accepting the fact that I may never lose weight. I've already started this process by giving all my too small clothes to charity and buying new clothes in my current size (as opposed to the size I want to be). I'm making an effort to look in the mirror and focus on my positives. I've started running again, not as a weight loss tool, but because I really enjoy that feeling of getting stronger and fitter and it's my perfect 'me time'. I'm also actively trying not to be self-conscious during sex with DH and just focus on the moment rather than worrying about what I look like as I'm pretty sure he doesn't care as long as we're both enjoying ourselves 
Anyway, just wanted to say thank you to the OP for such a thought provoking thread and good luck to everyone finding their paths.