Two stage login no longer working

For some time now, since a NIS update a little while ago, one of my websites does not autofill the login details as it did before.

Specifically, the website requires a two stage login - i.e. the first login screen asks for a login id (which Identity Safe correctly fills in for me); this then takes me to a second screen where it asks me to enter my "memorable data" item. Identity Safe used to fill in this too (it is stored as the password), but for some time now it hasn't done so.

The version of NIS I am using is 21.7.0.11, my browser is IE11 (and has been for some time, even when the two stage login autofill worked), and my operating system is Windows 7 Home Premium. By the way, I have the same problem on my laptop which runs Windows 8.1, IE11, and the same version of NIS.

The website that no longer autofills the second part of the two stage login is: www.nationwide.co.uk.

Any help, especially from a Symantec employee who has come across this before, would be greatly appreciated.

Many thanks.