I cant stress reading enough! We did only few practice papers and my daughter did outstandingly well in Nonsuch English. This is due to reading. Well done to you and DD for getting into your chosen grammar
1. If she will not read, read to her. I am assuming she spent some time each week preparing. Spend that time reading to her. It will be much more enjoyable than 11 plus practice.
2.Books like The family at One end street and Artichoke hearts (both award winning) are not necessarily on reading lists but are stories about girls and my daughter found that interesting.
3. Dont give up. Find the type of books she likes reading.
4. Go to the library. It is free. Pick up 12 books or whatever is the maximum. Let her reject 11. Even if she reads one, its is a start. Go back after a few days.
Modernista is spot on, reading is great. My dd did not enjoy reading much, but did like sharing the reading with me. I read a page and then she reads a page - I found that her expression came along in leaps and bounds too as she almost tried to compete with mine! Whenever something in the text has been implied, but not actually stated - ask her what she thinks it means and explain if she was unable to read between the lines. Also ask "what do you think is going to happen next" when the story appears to be leading in a certain direction.