Cate, i've been through all that custody/papers/lawyers/fighting cr@p so talk to me about it any time.

Basically as its been said it doesn't go through a court anymore unless every other option is exhausted.
Secondly, unfortunatley, there isn't much you can really do about what happens in the fathers contact times. You can ask for things to be done a certain way but there is nothing to force them to do it your way. I had issues with my ex's partner, who was just simply a nasty person. When I spoke to my lawyer I was told I had no say in who are around DD when she is in her fathers care, and that unless there was some form of abuse happening I had to put up with this person upsetting my child and saying awful things about me to DD.
The last thing is that the laywers and courts believe it is in the childs best interest to see their father regually except in exteme cases. They don't care about the 'petty' little stuff that as a mother we see as big issues. They believe kids adapt to the changes and to the different parenting.

Sorry that this was a pretty negative reply, i'm just going by what I have seen personally and with my closest friends that have all been through the same system.

The best thing to do is contact a family laywer and get some advice.