ADOS test

Hello all, we are having a lot of trouble gettinh a firm diagnosis for my 10 year old granddaughter.apparently she needs the bADOS test, but having waited so long to get to where we are now,really don't want to wait another 6 + months. does anyone know if we and where we can get this done privately in the London,Hertfordshire or Bedfordshire areas, and how much its likely to cost.. Thanks for any help...