Kmn - she does cooperate with me better to some extent... I can get her into my car seat without her kicking me. But she will also purposefully do something I've told her not to do and look me in the eye, wanting my reaction.

Again, thanks for the tips but behaviour management isn't really the question here. Her Mum is doing her best but what she's doing + me trying to block/intervene as much as I feel is appropriate is not enough to curb the behaviour. It's more about managing our relationship with things as they are.