The children at our local Primary where my DD attends all came out quite relaxed. There was nothing there they were not expecting - question types, number of questions etc ; some sections were harder than others depending on the child's strengths; a few struggled to complete everything in the time without any last minute guessing. When meeting parents from other local Primary Schools in our town over the weekend, their feelings were much the same
At the end of the day, my DD went in there fully prepared, aware of the time pressures, understood that it would be more difficult than the practice tests and that remaining calm, focused and sticking to a plan was the way to get through it. I have no idea whether she will have passed...but what I do know is that the foundations were all in place. She went in there fully prepared and as parents we could not have done more, and the rest was up to her and her natural ability. If that is not enough, then Grammar School is not the right place to be.
It sounds as though your school did a good job of making sure that the children were OK. my child had to take the test in a central location in a large hall with others she did not know. Although we do live in Bucks, we couldn't get her a place Ian local school so she goes to school over the border, there was no preparation for the test at her school and it was a very scary experience, going to the central location.