If you want your body donated to research (cadavers for medical training), rather than your organs, you MUST get it in writing and witnessed before you die. Because of the timescales on organ donation, lots of people who wanted to donate their organs can't.
Mum wanted to donate her entire body, but because she didn't have it in writing and witnessed, her wishes weren't considered. Whatever your wishes, make sure it's possible BEFORE you die. We knew mums wishes, and it's made it very hard on us not being able to carry them out.
We're all the the organ register, dad and stuart are now registered for medical research. If their organs can't be donated, they'll be going to a teaching hospital to help our next generation of doctors.