Hi. I'm a little familiar with the Terra Nova test. From what I can tell, and from what a principal from a different school told us, it also has a low ceiling.
Just as an FYI, the Terra Nova has achievement test sections (reading, math, science, social studies--with several sub-test breakdowns) but it also has an "in-View" test (which is more of an iq type test) as well. I don't know if you would want to go that route, but I thought I'd mention it.
You might look at seeing if there is a practice book your child can use. My dd's school spent about a week "prepping" for the test (taking a practice section each morning) and going over the answers. That way they know the format of the thing.
BTW, I empathize with you, and your child who is distracted in group situations. We've never had much luck with standardized tests with my older dd-- scores all over the board. The inconsistency can be maddening!
