This was last year's thread:
http://www.northstandchat.com/showthread.php?287385-Early-Warning-Brighton-Line-Is-Shut-Over-The-Christmas-Period
That was started late September so I'd guess nothing as major is planned this year :shrug:
There were rail replacement buses for:
Middlesboro (H)
Watford (A)
Spurs (A) (on the return journey)
It's a shit sandwich that we all have to take a bite from a few times a season.
EDIT: Just seen that it will be buses between Brighton and Three Bridges for Charlton away (10/01/15)