I thought most places tested English and Maths....
. (I know Bucks doesn't),
Medway, where my DC's have taken their tests, not only they have to do English and Maths, but they are counted twice, while the VR paper is only counted once, which means if your english and maths are not good you will not pass.
What do you suggests? surely not for the primary schools to decide which children are GS and which ones are not ( what a huge can of worms that could be!)
It is not a horrendous process, unless you make it so. If your children are motivated, and want to do it, it's actually a very rewarding experience.
You do not have to have a private tutor, as it can easily be done at home (I have done it twice), so money does not come into it.
Also, IMHO, it has taught my DC's study skills, and it has been an invaluable tool in learning exam techniques( timing, prioritizing content, etc) , something that they will use again and again in their academic lives, so all in all a worthwhile experience.