Taj, I understand how you are feeling as I was thinking the same when my son started year 5 (He took both Slough and Bucks tests two years ago). I opted for a tutor at first because there was hardly any advice available at the time, but having prepared him myself in the end, I think thatï¿½s it is easier to get to grip with DIY than I thought at first.
No, I didn't use the main tutor group in Slough. Would I go for them now? No, I would DIY, not only for cost reasons but also because DIY tuition is more targeted to the child needs and wastes less time. I would not like my child to have to give up most of his after school life as some of his friends had to do.
The Slough tests comprise three papers, all NFER multi-choice: verbal reasoning, non-verbal reasoning and maths.
For VR, the preparation for the Bucks tests is more than adequate for Slough.
See here for Bucks VR preparation
As Patricia mentioned, the Bucks VR has 21 questions types, whereas the NFER papers show 15. We are not sure for Slough, but practicing more types won't hurt. See topic 'Unanswered questions about the Slough 11+'
Just a comment specific for Slough:
Patriciaï¿½s advice about starting VR practice in the New Year is for pupils who only prepare for the Bucks tests. In my opinion - I am not an expert - it is worth starting earlier if you also prepare for the Slough tests.
This is because these is more to do, and also because of the maths.
The NFER maths syllabus goes well beyond year 5 curriculum, so year 5 curriculum will have to be topped up, and I think it is best to start from what the pupils will have learnt at school rather than starting from scratch something that they will learn at school anyway.
For example, your son should learn the principles of algebra in year 5. It is nothing compared with the NFER algebra, but a good foundation to build up more advanced knowledge.
That's why I think that is a good idea to start with VR and NVR and free up time for maths later on during the summer term.
In term of maths practice during the year, I would just concentrate on making sure that your son has a very good grasp of year 5 curriculum and practices
-Mental maths, and timetables
-Operations. The ae publications books advise familiarisation with long divisions and multiplications. My opinion is that theses methods are more efficient that some of the new methods, and worse getting your son to use them fluently. But again, this is just my opinionï¿½
I used the ae publications book as reference and to dip in and out. I found them useful because their content is geared towards entrance exams rather than school curriculum, but I thought that sometimes the approach was more of a drill about how to do things rather genuine explanations of mathematical concepts.
Hereï¿½s some links to previous discussions about the preparation for Slough tests
Slough 11+ preparation
11 + preparation
As for NVR, I personally think that it is not as complex to teach as VR, but you may want to read as much as possible of the non-verbal reasoning section, as most of it is about the NFER tests. The maths section also contains some good tips.
I'll stop here for now, but please don't hesitate to ask as many questions as you need.
If you need specific advice about maths, NVR etc.., ask on the relevant section, as you may get help from parents from other areas also using the NFER tests.