I had the same situation as Andy. Here's how I was able to reset the page index to 0.
In the event handler that calls the Rebind method, find the RadDataPager control and set the CurrentPageIndex to 0. Even though I had a top and bottom pager, resetting just the top caused the other to reset as well.
sender, SearchBoxEventArgs e)
var RadDataPagerTop = (RadDataPager)RadListView1.FindControl(
RadDataPagerTop.CurrentPageIndex = 0;