Good idea.

I am/was going to try and use a white light filter from some old PIR sensors.
Also extend the TX LED away from the photodiode's.

Hopefully if the repeaters TX LED's are bright enough it will punch through the "noise" from the N900.
Failing that I will have to block the TV's RX from the room so it can only see the repeater.

As I said not had time to play, got other priorities ATM.
Thought the schematic was worth sharing while I remember.