Yes, you can do it from Spain - provided that your son's current school is to let your boy taking the 11+ at the school.
Yes, you can do it without hiring a tutor - provided that you're prepared to spend some time with your boy.
I did this myself - I helped our elder boy preparing the 11+ while our family was in Australia back in 2009.
(And now helping our younger boy for his coming 11+ in Oct)
Let me share with you of our last journey.
My wife and I started thinking about relocating back to UK around May/June 2009. Our UK friends told us that we should consider applying grammar schools. After doing some research and checking the Times League Table at the time (only 2008 results available), we had shortlisted 3 grammar schools in the Top 50 (for better academic results), which were Outside London (for less competition) AND Co-educational (for a more real-life environment)
The three grammar schools we picked were :
Sir William Borlase's in Buckinghamshire;
Pate's in Gloucestershire; and
Colyton Grammar School in Devon.
We applied to the above schools/the related councils around July 2009. All 3 schools agreed to let our elder boy to sit their 11+ at his OZ school, supervised by his teacher and then sent the papers back to UK for marking.
The first 11+ our elder boy took was the Buckinghamshire's, in September 2009. The Buckinghamshire Council was really helpful as it had sent us a lot of useful information (e.g. advising us every student was supposed to take 11+, parents had to write to the council if they did not wish their child taking the 11+)
The Buckinghamshire Council posted us a pack of six 11+ papers (Verbal Reasoning): Two were a bit like 'Warm Up' paper and the council instruction was to let the child do these two first before trying the remaining four papers on later days. It also advised us there would be two VR papers for the REAL test and the better scored one would be chosen to 'rank' the child. (Can't remember if both papers were taken on the same day as our boy took 3 separate 11+ from 3 different councils)
The Qualifying Standardised Score at the time was : 121.
We used the above 6 papers for practise, then a few online 11+ papers plus us buying on Amazon UK site a pack of Verbal Reasoning (contains 4 papers) and a pack of Maths (also containing 4 papers). Our younger boy didn't get the Qualifying Score as the Buckinghamshire's was the first 11+ he did, and the 11+ Concentrated on VR only.
But our boy did better in his second 11+, he was ranked 133 on Pate's and was put on its waiting list. Although the school had 120 places only, every year Pate's ranking candidates up to the 160th as it had offered places to those on 15Xth due to some not taking up its offer for various reasons. (e.g. job relocation, couldn't sell house, accepted by another grammar)
Our younger boy did best on his third 11+, taken in Nov 2009. Three different tests in one morning. First, Verbal Reasoning (50 minutes), a break, then Maths (50 mins), another break, then Writing (2 piece - 1 hr?) He was accepted at the Colyton Grammar School.
During the 2009 process, we had found the following facts,
1) It was about 1 in 9 chance in getting into Sir Willaim Borlase's, about 1 in 6 chance for Pate's and 1 in 3 chance in Colyton Grammar;
2) There were about 8,600 students eligible for taking the 11+ in Buckinghamshire at the time but only about 8,300 took the 11+; and
3) Because we made an appeal, we had received additional documents from the Buckinghamshire council to prepare our case.
Its paper showed there was a 'Drama' took place in 2009. When it was getting closer to the Real test Day, there was a rumour that the paper was leaked, so the council decided to use an old paper instead, which was the 2008's paper, yes, the paper used just the year before! The council's document also gave a detailed breakdown of the number of candidates for each standardised score (i.e. from 69 to 141) I was surprised by the number of candidates getting the highest score of 141 - which was significantly higher than any other score, higher than those getting the lowest score of 69 and the qualifying score of 121.
We only started giving our boy some practice papers around late July/Early August (mainly from Buchkinghamshire council) for the 1st 11+ in Sept, then with Amazon's purchased papers from late Aug for the 2nd & 3rd 11+ in Oct and Nov respectively.
The first thing you need to do now is to contact the schools you are interested in - there is always a deadline and are some conditions imposed by the individual school and by the council.
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