Not sure what Cityfibre install but Toob use an Adtran SDX620 series there are a few variants but it’s the 1GBE version.
The LEDs are
Power ( power symbol)
Optical (laser symbol) if it’s Red then you have no optical signal)
Ethernet (computer symbol) - flashing green = activity.
Normal operation is Power and optical should be solid green, Ethernet should be flashing Green.