@ChopinandChampagneI am so sorry that this has happened. I'm especially saddened that you seem to be blaming yourself exclusively for the current state of affairs. I know that you wish you hadn't said certain things, but TBH one can tread on eggshells for only so long. Everything really comes down to money and gifts with your DD, and as soon as you pushed back on lugging so many items to Ireland, she exploded.
Remember what you posted just a couple of days ago: "LB is now apparently saying what progress we have made and welcomes my visit."
And this: "I said the issue obviously went back to the original house, a long time ago now, but the concerns regarding trust related mainly to not advising us of the birth of DGD1. She seemed to accept that and said she thought that things were 'forgiven and forgotten', which is the first time she has alluded to 'forgiveness'."
What has changed since then? Nothing, except your messages about being hesitant to serve as an unpaid courier. Does she usually take that imperious tone with you? I don't mean in the final message, just in the text exchanges, e.g. "I can call you to decide what is important. You will want to be bringing your presents for the children DGD2s birthday. You should have sent anything from amazon directly here!" So rude and disrespectful.
As for her last message, there is some world class projection going on: "You have been very cruel and I believe you do it with an intent to hurt me and manipulate me. You have a warped memory of the past. A warped past which you clearly have no desire to let go of." She is accusing you of exactly what she has done.
I know you love your DD and want to see the best in her. But she continues to be appallingly cruel and manipulative to you. And I can't agree that she's behaving as a good mother should. She is allowing her very young children to live in squalid and potentially dangerous conditions when she has the means to change that immediately.
I do hope that you are able to enjoy Christmas even though you are coping with this extraordinarily painful situation.