Great post, Tiggytape.
I went around many Preps and was struck how many children would be able to do 11 plus papers standing on their head. In some schools timed tests were routine from Y3 or even before. 11 plus targeted homework was given at least twice a week from Y3 etc. One near where we were in the UK was non selective and nearly everyone passed for the local, highly selective grammar.
I feel for the PP that talked about crawling through the test with their child. I know what they mean. Thing is if they are at a school where they prepare for so many years it's absolutely second nature, falling of a log and something to be enjoyed even.
I remember visiting a prep and a Y4 class were doing a timed test, one of many they did from time to time, the atmosphere in the room was absolutely calm and the children didn't appear under pressure. This was clearly absolutely normal for them, standard, fun even.
Our school offers a few sessions of VR etc and we are told that's all a bright child needs. I don't think many have any idea how advantaged those are at Prep schools. If it wasn't so unfair it would be side splittingly funny, they have absolutely no idea whatsoever. How many have routine, daily practice against the clock for literally years before the 11 plus? Timing is just one aspect but it trips so many up.