Ok - solved my own problem
there is definitely a timeout - you have to enter the new password and verify it - within a ridiculously short period of time
I could not get around this using Putty - as it does not allow pasting
I used the Powershell SSH client (open-SSH) after downloading it
I was then able to copy my new password from a notepad and then paste it, right click into the shell, within the allowed time period - which i'm not sure what it is - but way too short to allow you to type a complex password and then retype it again to verify it
this is a significant bug