Received a message that inverter update time failed after 100 attempts. Suggested that I set the time via the portal. However in the "Time and Date setting on the portal, there is no mechanism to enter the time and date just "---" and send, which is/are not editable.
Setting new time
Go to the account settings part of the portal, timezone gmt (always, not just during GMT), then sync button.
Contact GivEnergy support.
I received the same message as Stephanjs but can see that the inverter time seems to match GMT. A related question though- as I don't have solar all my charging is done in cheap times. Can I set the inverter to remain PERMANENTLY on GMT (like my E10 meter?)

Mine was incorrectly set on installation to GMT+1. The time was BST at the time which is GMT+1 but the setting means London and should always be on GMT. I changed it to get my graphs to show the correct time, etc. I don't think it ever changes itself.

Ensure account is set as GMT always.
On remote control page. Just hit send.
Then you can if you wish read back the time and date registers.