WHS like many selective independents all do their own "11+" based upon VR, NVR, English Essays, Maths, Science, interviews. Some do a couple of papers, some do all, or their own special mix. It is not really the 11+, as in grammer entrance, that you are doing.
If you are at a prep school, your DC shouldn't have a problems with these types of tests, as they will have been doing them all their lives, and certainly in the ones I know they ramp up the revision of these especially in time for the indie school examinations. So, I haven't seen that tutoring is big in these schools. I am sure we all do some books at home, but that is not tutoring, just practice.
It is a shame you daughter didn't get accepted in the first cut. That is not to say she isn't bright, or talented, but just that she doesn't fit WHS. Many of us have been there, you don't get an offer for your first choice, but my goodness, you may well end up at the perfect school for your child. IME indie schools are pretty good at picking the right candidates for their school. Get you DD to do some books over xmas, but don't make it the be all and end all. I am sure she will succeed wherever she goes.