After being down all night, I just rebooted the Hub 3 and it is now currently connected, with both on 64 qam.
But the recorded message is still when you phone up, so I expect more issues.
I just checked the error log on the Hub 3 and have a the page is full of:
017-07-12 05:35:18.00 82000700 Unicast Ranging Received Abort Response - initializing MAC;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:yy:cc;CM-QOS=1.1;CM-VER=3.0;
2017-07-12 05:35:18.00 82000200 No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=yy:yy:yy:yy:y:y;CM-QOS=1.1;CM-VER=3.0;
This is the last one in the log, you need to add an hour on to the time, as the Hub 3 is running in GMT/UTC timezone and UK is in BST +1 on GMT/UTC