L322 Fibre Optic Light help

Hello
I have the front screen stuck on the logo and the flashing light on the power button.
After reading loads of posts on the subject i tried the bluetooth bypass which did not work.
Before i go any further i noticed that all the plugs i pulled from the units in the rear have a red light but this is flashing and not solid. From all the posts i have read i don't think this is normal. Can anyone confirm please and offer any advice.
Thanks

The MOST (Fibre Optic) Circuit starts at the Integrated Head Unit which is behind the Touch Screen Display, it goes from the IHu to the Touch screen display and then to the CD Changer in the glove box before going to the rear of the car. Take the dashboard top off to gain access to the Touch screen Display and IHU and check if the light if solid or flashing,it should be solid.
You will need to remove the glovebox to check the CD changer (there's a how to on Youtube). Use the bluetooth bypass to check each unit to see if the light is solid when you use the bypass
On my 2006 L322 a previous owner had connected the fibre optic cables incorrectly in the back of the CD player, swopping them round solved the problem after it had been into a Range Rover specialist and an electrical specialist who could not solve the problem.

May be easier to start in the rear corner at the satnav as that's easier to get to. If it's flashing there then go back to CD player as that's a PITA to get to.

Just re read the OP's post and it states he's checked all the unit's in the rear so ignore me