Many assume that if you home educate, then your child will not be able to take exams. Not so, just it can be a little tricky logistically, but once those issues are overcome then it is fairly straightforward. I will endeavour to explain the steps below.
1) Decide which subjects your child wants to take.
I would say the most important are English, Maths, and the Sciences. (In doing this, it may be pertinent to ask, are these actually necessary? I will add that qualifications are not quite as important as most seem to think. Employers being primarily concerned with how you present yourself, teamwork, and interaction. None of these can be taught in the classroom!)
2) Choose an exam board:
Now, there are about three options as far as I know. Cambridge, edexcel, and AQA.
We opted for Cambridge I.G.C.S.E as it is more rigorous, and it offered alternatives to coursework. The subjects chosen were Maths, Chemistry, English Language, and Physics.
3) Thoroughly check the syllabus, but before buying any books check out the exam wiki http://he-exams.wikia.com/wiki/HE_Exams_Wiki Alternatively, check the exam board's list of accredited schools. (these will all be private schools) Don't be afraid to ring them, and ask to speak to the exam's officer.
4) Finalise the 'sitting' arrangements. Once you have found a school willing to take on external candidates, you will then obviously want to register for the exams. This is usually done in January for the Summer session, and in September for the Autumn session. (though some boards sit in January)
Schools differ here, and some will want you to have an identification card. We just had to attend a pre- interview where all that was covered.
Also, check your local home ed group. Some have private exam centres.
I hear you wondering how much this will cost. This will differ from school to school. Expect to pay around £100 per exam, and pay for an invigilator, too if needed.The C.I.E exams cost around £50 each for I.G.C.S.E. The extra cost is the school's administration fee. Sometimes the admin fee will be a one off per child. As for buying the books, check on Amazon. Often they have slightly outdated books for a fraction of the cost. Just make sure you know all the updates on the syllabus.
We didn't engage the use of tutors, as the expense would have been too much. Don't be afraid thinking you don't know enough to help your child. My subject is not Physics, but I was able to help my children in early home education develop the skills they needed to research, and do more self directed studies! Difficulties can often be overcome by google, or a friend in the know!
Remember, if you do take this route, that you will be representing the home ed community as a whole. It is important to be on time, courteous, and well turned out. The schools don't have to do this, and it sometimes can create a lot of extra work for them! I spoke to a teacher who had been overwhelmed with the numbers sitting externally, so much so that she had chosen to stop taking candidates altogether.
To conclude,some people get into a worry about home education. They think their child won't sit exams, and won't get to Uni. However, consistently this has been proved wrong. I know many home educated who have done exams, and gone onto Uni. I will also say qualifications count for little in the real job's market, as my eldest has been finding out. We all know the names of those people who made it to the top with little, or no qualifications. In short, employers want people who can work on their own initiative, can engage with all age groups, are positive, and always ready to learn new things. None of that can be taught in the classroom. This is where home education can have the upper hand. Our children haven't become dependent on being spoonfed, and are instead able to research and study for themselves. Skills which are an imperative in University, and the working would.