I guess I should update this:
The error spikes at night have been attributed to bitswapping errors
Long technical thread and have been fixed in the latest firmware update from sky. My router can now stay online with no manual reboots (I have a good line - your mileage will vary), so I'm a very happy bunny.
Sky have changed their email system to a google mail type thing, you can set it up to forward it to your pop3 or IMAP client. Only cripe I have with it is spam doesn't get forwarded which sometimes ends up with you being unaware of important mail.
The sky DNS problems have also been fixed.