I started looking at 11 plus papers and doing extra maths work with my dd2 about 9 months before the test, we couldnt afford a tutor. Luckly she passed, but the work I did with her would have been worth it even if she hadnt passed as her maths was below average in the class and the extra work we have done brought her up to top table level.
dd1 is in yr 10 now and did go to group tutor "11 plus club" sessions, so i didint do work with her at home. She passed and as we speak is stressed with her mock gcse's
I think to even out the playing field, so to speak, the
schools need to prepare the kids for the test from maybe 6 months before the date. They prepare them for the SATs so i cant see why this would be a problem and it would mean those children from poorer familys or with less "motivated" parents would stand a chance in the test.
I know of a few bright children at my dd2's school who with a bit of 11 plus practice and help with problem solving could have made a good attempt at the test but as it is never even did it.

Its a shame.