That seems wrong to me. Withholding info just comes across as spiteful. I'd let her know in passing that they called. Something like "incedently AC called, your cars dues it's MOT" and take it from there.
Me:43 Her:42 M:14 S:9 EA started 2014/03 (or there abouts) PA started 2014/05/30 BD:2014/11/05 I left 2015/10/01 I returned 2015/05/02 She left 2015/06/10 OM still on the go.