When I was in the police and I went back to work after having the children I went part time .
My children were in a day care nusery so had to have set days each week, so I worked my shifts round that.
Children were in day care every Monday & Tuesday , i worked every Monday & Tuesday, Saturday Sunday with my team whatever shift they were with the exceptions of nights when I worked Friday Saturday Sunday Monday nights.
we had a five week rota but longer hours , it wasn't an 8 hr shift it would be 9 or 10 hr. One week in five I would work an extra day , so either Dh would take day off or I would see if they had space at the nusery that day.
My DH is also in police but works 9 to 5 ( ish) and was able to have the children when I was nights , at weekends and do pick ups and drop offs at nusery.
You should find the police very accomdating in their atttude . I had no problems .
as the rota is planned a year in adance she should be able to work out a suitable pattern , she needs to have a word with her duty office or whoever is in cahrge of the rotas.