Here is Honeywell's 2nd response. This is after telling them that the issue affects both Android and IOS, and is a different issue to the one they has been fixed:

From: consumersupportuk@honeywell.com
Sent: 08 November 2017 14:53
Subject: RE: Bug in the Honey Total Connect Comfort App [ ref:_00D00hZKZ._50080159Ifq:ref ]

Good afternoon,

Thank you very much for the confirmation.

We would like to inform you that the issue with iOS11 was resolved, and the application should work correctly now.


In case you are still experiencing difficulties, please do not hesitate to contact us again.

Kind regards,

Kasia

E&ES Europe Consumer Support
Honeywell | Environmental & Energy Solutions Europe