you could try asking at your GPs office or indeed telephone your local hospital and asking for the occupational therapy dept. They might have a contact number.
I totally understand how you feel. I too have five children and although my very straight hair is only just passed my shoulders, if I want it too look nice and have anything other than a french plait, I have to take an hour to blow dry it under. I have 4 girls as well so when we have somewhere special to go, I have 4 girls and myself to do the hair of: I am considering a crop myself!
i think what you are considering, is so kind and I hope you find somewhere to donate your hair to.