I would mention the fact she didnt greet you and make it obvious why you didnt feel the need to say bye or just be polite and say she looked busy so you didnt want to interupt make her feel silly.
Thanks - actually that's more or less what I did say in a text back to her! I tried to call her first but she wouldn't answer her phone. I said sorry it had upset her that much, it wasn't our intention but we were a bit disappointed that she hadn't greeted us or said congratulations on the baby. And that she seemed so busy that we didn't even think she'd notice we'd gone! I ended it nicely, saying I hoped it looked a bit different now, take care etc. But she hasn't answered and I don't think they'll ever speak to us again, and I'll always be bitch from hell!
Funny thing is, DH was more annoyed by her at the time than I was, and he said to just leave and not bother with her - and if I'd tried to find her myself she'd have had nothing to moan about (only DH, and she wouldn't have dared)