So....this is the best I have found....
It's simple and in cartoon, so hopefully not too "disgusting".
I'll let you know soon what they think!!
Update: 5th June 2014
I spoke to my class about my operation and showed the video today, and their reaction was full of interest.
Most watched the video all the way through and despite a few 'urgh's, they were really interested in how this worked.
They asked really sensible questions about how do you change the battery.
Overall, I'm glad I showed them.
I overheard one child explain it pretty clearly I her mum, despite saying I had "nerd damage"!!! ☺️
A few even wanted me to write down the link so they could show their parents. Bless them.
That's at least few people, in the next generation, who now have a bit of knowledge about this terrible and little understood condition.