She has by now thought that Wentworth values her at some level - that his helping her into the gig was an impulse of pure, though unacknowledged, friendship.

Yes, I agree, Lyme and her discussions with Benwick, are a real a turning point. I think this continues with her lovely way of listening to and supporting Henrietta the next morning. Both times she is amused, by her own giving of such advice in the first case, and by Henrietta's expressions of awe about Lady Russell. This amusement, described by the ON, is cheerful and has no sardonic edge to it. Earlier in the novel, the ON's descriptions of her inner thoughts often have such an edge - though it is debatable whether it is Anne or the ON who actually feels that edge.