Thank you all so much. I've finally got it working. I used the same query I had at the beginning, with the same calculations, and now it works!! All the lines are shown exactly as I want them and not scrolling up. I don't know exactly which step I did that made it work but it does not and I'm not going to stress about it!! (At least, not until the next problem!)
Thanks you all for your help. I suspect you'll be hearing from me again as I get deeper into the project. Note to self - never offer to do things for family!!