If you dive deep into the Asus support website you will find a page "Transformer Book T100HA touch panel abnormal." [http://www.asus.com/support/FAQ/1015157/]
this tells you to:
"If your touch function does not work or activate , please download update tool of the touch panel and execute . Then, allow the system to re-do the touch panel adjustment. During adjustment process, please do not touch the screen to avoid adjustment failure . If you have touched the screen, please re-executed once."
It was a pain in the **** doing this but it did work.