NTP Settings / Time Zone Setting Ignored / Reverts Back

So now that I managed to get my new Nighthawk R8000 working on my Sky Ultrafast connection... I'm having an issue whereby the internet connection is dropping precisely every 24 hours. I'm at a semi-loss as to why it is doing it, but it has done it for the past 3 days. The router logs show the disconnection, but not the reason why. If I tweak a setting on the router to cause it to reinitialise the connection, it seems to come back without too much fuss, but clearly something's not right. The old Sky router never used to do that, so tonight I've changed the Internet mac to match the old Sky router. I'm crossing my fingers that that fixes it, but I'll have to wait until tomorrow night to find out. One other thing I picked up on, was the NTP settings. It is currently set to Netgear default, and the time zone is incorectly set to International Date Line West (GMT +12:00). Every time I try to set the correct time zone, it just reverts back to the wrong one. And if I try to set a public NTP server, it just reverts back to Netgear default, and I have no idea why. What i want to know is... Is that a genuine problem, and could it be causing the DHCP lease to expire after 24 hours? The actual time does appear to sync correctly via the Netgear detault setting, but Time Zone does not... Answers on a postcard :)