my son took grade 1 at 4 yrs old and grade 3 at 5 yrs old (we skipped grade 2). both got distinction. It was pretty easy and didn't require much preparation. There are video samples of the examination in gese website. you can take a look.
I have Trinity GESE Grade 1 Textbook ("Talking Trinity", edition 2017) for selling, the condition is very good, $90, anyone interest? Please pm me if you need.
may refer to below link for reference.