The lot of them... the Network Rail site contains the current WTTs, and the Dec 13 ones must have been widely circulated by now...
The 12 weeks is for STP. By rights the WTT is completed months before that (not least as STP have to work in the LTP to get to said 12 weeks...)Timetables aren't finalized until 12 weeks before the change date. Which should be this Sunday coming.
Having said that it can sometimes take a couple of weeks for NR to actually get round to publishing them online.