Welcome TillyJ!
Many of the members here are about your age, including me. I have often wondered at the timing that causes us to begin to figure out what is and has gone on in our lives now that our children are grown. I think that I finally began to see things more clearly and had more time and attention to focus on me. Perhaps you are in the same or a similar place? I'm glad you've joined us. There is a lot of information here to look at, and the resources Drained1996 mentioned are a great place to start.
I have read so much over the years and have coping mechanisms in place - but am now getting really upset at how messed up some of my siblings are. I am a 'rescuer'
Kudos to you for all the work you've already done!

Sounds like you've made some great choices, and you are wishing they would now too. The effects of a BPD upon her children are astonishing, causing chaos in lives, the inability to process or feel emotions, and basically in a nut shell, arrested development. Have you read the book
Understanding the Borderline Mother or
Surviving a Borderline Parent? The first is quite long and detailed, while the second is more about the effects upon us, the kids. If you've not read them, let me know and I will post the book reviews for you.
Do all of your siblings bother you with their inability to act like adults or just certain ones? Sometimes I look at my siblings and wonder that we had the same parents. They were each affected by our uBPDm, but since we each have a different personality, I see it playing out different in each of our lives.
Wools