Attempting to route between 2 subnets but this page doesn't seem to save any inputs. Clicked Add + Apply Gateway is 192.168.1.11, destination is 192.168.0.0 subnet. (router is changed from default to 192.168.1.1)
Please can you get another screenshot prior to trying to save this, in case you are trying to enter anything wrong? When you include the screenshot in your reply, please make sure that the "Large" size is used within the Insert Photos option. Otherwise, your screenshot is too small to read & when enlarged, the text just goes out of focus.
Then I will see if I can replicate the problem & submit it as a bug to TalkTalk.