Take it from someone who pulls them out of the rack. The message LGCIU 1+2 means two dead LGCIUs.
I am not ruling out a signal could not get through if the fault is an internal card failure but again more than likely it will be completely dead no indication, you can't get the lights if no power or if the downlock sensors can't get the message through.
Your FCOM will cover all the angles and scenarios, I am saying the practical reasoning of this fault.
Beeline out