Well, here she is, shaved all over, all matts and tangles removed, and even though I thought I'd prepared myself, I still feel like crying.
The groomer said, the matts under her armpits were so extensive, that, once she'd removed them she would have had to do the rest anyway because it was so obvious.
She also said, that the she thought the matts were left from last time, when she went to a different groomer.
Still, it's done, and hopefully, it won't have to be done again, ever.
It's weird, she seems to be all legs now, and, I also discovered, a bit chubby!