B.-
First, let me say that I've gone through just about the same thing! My daughter's father stopped speaking to me when I wouldn't abort and only stayed involved in my pregnancy minimally, at the demand of his parents. He asked for a paternity test 8 hours after she was born. Even when that came back proving him to be the father, he either wanted to take my daughter by himself (as an infant he spent maybe 2 hours a week with her) or just didn't come around. He moved to Chicago (from Kalamazoo) when she was 18 months old and to Philadelpia when she was 3 and a half.
So, I'm a single mom, too and my daughter's father lives over 700 miles from her and hasn't visited her since April of 2009. His parents live near Kalamazoo in Richland (20 minute drive TOPS!). They also bounce in and out of my daughter's life and only see her once every 6 to 8 weeks.
I've asked that things be a certain way for consistency for my daughter from her father and his family for 6 years. I think it's important that if my daughter is only going to see this side of her family once per month at most and once every two months typically, my input on what how to care for her and making her comfortable should be valued, respected and seen as an assett. I'm with her every single day, I am the person in her life with the most knowledge of what she wants, needs and is used to. I have begged for consistency for such a long time, with no improvement that now, I go with my daughter when she is going to spend time with her grandparents. I konw that might not be an option for you, B.. But, Mama Knows Best and if you're asking for consistency so that your daughter is as comfortable as she can be dealing with a blended family, that is well within your rights and responsibilities as a mother.
Communication is a very important factor, especially in sitautions where the parents are not together. I feel that the parent the child spends the most time with should be able to set the guidelines. My daughter changes so much from month to month that these visits become a disruption when they don't happen consistently. They all just want to play with and pamper her, not knowing what else to do because they don't see her regularly. Then I have to deal with a whiney 6 year old when she returns!!!
I think you are right to state your feelings, make your expectations clear, and leave the responsibility as to whether or not there will be better consistency up to the people responsible for providing this to an innocent child. Keep asking for what you want and, though you may need to come to some sort of compromise, keep asking until you feel that your daughter has what she needs to create and build healthy family relationships. It is our job as Mamas to do what we feel is best for our children, no matter who disagrees!