@Macca76 

Hi, Did you set up any reboot schedule on the SKY router, or would ISP maintain their service automatically at night?

If the same issue repeated next time, could you please help me check the following details:

1. Did the SKY router keep working when Deco was red?

2. Please open the Deco APP at this moment, then go to More>advanced>IPV4,  can I have a picture of this page?

3. if not resetting the Deco, just taking out the cable from the main Deco to SKY router, would the connection recover later?

4. Please try to log into the web UI of the Deco when it was red via http://tplinkdeco.net and save the whole system log to us;

Thank you very much and wait for your reply.