Hi Mama H,
I self tutored both DS1 and DD for the Kent and Medway exams, both passed well, so I must have done something right
I grant you, finding the time with 2 siblings (I'm in same situation), wasn't always easy but we got through it unscathed!! I decided that the noise or distraction from the siblings was allowed for two reasons, one was that if I wasn't stressing about complete silence then it was all the more easier to keep sane myself
but the main reason for me (and that which I told the children) was that it would be good for them to learn how to concentrate on what they were doing without letting themselves be distracted by any other noise or goings-on, so that in the event of crying, talking or any other distractions in real exam, they could learn to ignore and carry on regardless.
I used this wonderful website for loads of information and bought many varities of books, papers etc including the Bond/How-To-Do books, these allowed me to cover all the gaps in DC's learning that would be relevant for the tests. If one DC was doing some work then I would set some work for the other 2 that was relevant for their age, e.g. wordsearch books, activity books, drawing, puzzles anything that really kept all minds busy at the same time so that no-one felt more pressured than anyone else.
Feel free to message me for more info or reply with any questions and I'd be happy to help where possible.