I've decided to take a different approach with my DD, she's an (normally) easily distracted type of child, particularly to others needs. I started off with her in a quiet, uninterrupted environment and then took the conscious decision to scrap that idea and encourage noises, sounds & little brother to be around whilst she is working. My logic (albeit mad) for this is that I've heard allsorts of stories of children being distracted during their exams by maybe crying children, ill children & many other possible scenarios and I thought it would be better for her to get used to ignoring whats going on around her whilst working. So, I've had younger DS doing his own work, drawings, watching TV you name it, in the room whilst she's working and so far it's had no adverse affect on her learning whatsoever, getting full marks almost all the time. Obviously all children are different but she's managed much better than I could have hoped & I've explained to her that in her real exam there may be things to ignore and she's accepted that quite happily.
I will be doing quiet work with her also, particularly when she's doing practise tests but I'm not going to worry too much about distractions until her work is affected. Then it'll be snacks & TV at the ready