Thanks GreatDuck it's nice to hear that.
I wish to god I had discovered Mumsnet at the time as I had never heard of that kind of behaviour and I was completely floored by it (as well as by having a baby!)
she got better over the years, but it's been pretty awful seeing them ever since, and has caused no end of conflict between me and DH.
The difference with my own mum was that when I was telling her about mil's outburst re post natal depression etc, she said
"That was 35 years ago. It's you I'm concerned about"
And that dynamic - that for mil it was all about HER, her issues, her ego, her wants - for my mum, MY welfare, not her own, was her primary concern.
That's why some women want their own mothers and not their mothers in law.