My daughter took the 11+ this year in Plymouth.
She had an assesment in Jan 2010 with IQ of 115 which is apparently where the grammar school would like them to be on entry so the tutor was happy to take her on. I assume most tutors will only take on children they feel have a chance as obviously if they didnt their pass rate may go down, but then I expect you also have tutors who just want the money and will take them on anyways :/ it is a rather grey area. We chose our tutor as she had tutored my step son who passed. She said she had percent passes of 98 for boys and 95 for girls.
My daughter went once a week for an hour in a class of about 8. I did 2-3 tests a week at home with her. the tutor cost £12.
Please note I do not know if she has passed yet until tomorrow.
My advice -get yours in for tutoring immediately as others will have started now. Ideally they need to be at level 4 in year 5 in maths and english or working toward it and working at least toward 5's in year 6.
However my daughter is working on secondary school maths in yr 6 yet another who took it is not...so I dont think just because they are not they shouldnt take it. Your school can definately give you an idea of wether your child stands a chance, even the level my daughter is at I dont think she will pass as you see others children on here who seem way ahead and they dont pass sometimes :/.....
I know of someone within her group who got a higher IQ score than my daughter but my daughter did better in the mock....so unless your child is right at the top of the spectrum expect to never really know their chances for next year.
As for tutoring well I think you should speak to your school and if they think its worth a go get your child assessed by tutor asap. (some teachers can be a little opinionated re 11+ so if you find this talk to another and dont be put off)you may not need a tutor, I know of a girl who was not tutored at all and got very high marks in mock.
I however think it is important to keep one step ahead of the game if you can afford to(touchy subject in plymouth). my daughter could get every answer right in the tests but couldnt do it within the time..she had NO time management skills she is too laid back, this is where she benefitted from tutoring, the tutored honed her skills, she didnt really need help with the questions it was time management, something I felt I couldnt teach (im a stress head!)
Also note there are maths areas which they DO NOT cover in school, you or a tutor will have to cover them.
I liked both GS to be honest, I felt DHSG was a little more regimented and not as 'family' atmosphere as PHSG. DHSG also had probs a while back and was in newspaper but that is all sorted now. I wanted to put PHSG as first choics but my daughter wanted devonport...I dont think we are fussy with either...just a GS education will suit us. ~If they are suited to that education they will do well at either school, just go along during school hours for a visit and get a feel for the place.
hope that helps