I think DIY is the best option for us, but I am worried that maybe I am missing something important out and . Also where to do the working out, are they allowed to write on the paper or on scrap paper.
Also Blanca mentioned that
This years tests were stanard format with children saying vr was harder than expected.
does this mean that the format of the exams vary year after year. If so by when do they announce the format for the next year
They have been standard format for as long as anyone can remember. When my son took the tests in 2006, working was done on the test paper.
The maths papers have been supplied by NFER for some time; there is no reason to expect this to change. It's essentially KS2 maths, tested in a different format.
The VR paper changed a few years ago. Reports (e.g. from the 11plus forumadmin) are that the 2007 paper was supplied by Moray House. However there are a limited number of Moray House papers, which used to be available for general sale, and some have stockpiled them. This is reported to be the reason that St. Michael's in Barnet cancelled and reset their VR and English papers last year. If the consortium schools have any sense, they will switch to a different supplier to avoid a similar debacle. So it might be wise to practice a wide variety of types to avoid being taken by surprise.
They do not announce the format. Admissions secretaries will answer the question, but there have been reports of misleading answers regarding VR. They will also say that all applicants will be sent practice papers, but in the past these have been next to useless, a single sheet with a few maths and VR questions.