Hornbill88 - I did trawl back and find the reference to some Twitter feed which then led to the Reuters report, which spoke of sources who wished to remain anonymous. It indicated that the postulated track of IGARI-VAMPI-GIVAL, then possibly IGREX, was put together from military radar (presumably primary?)
Still not convinced it went west at all. Came across this which quotes another unnamed source as saying they now believe it is off the coast of Perth:
Combing Ocean for Flight 370 Harder Than 2-Year French Hunt - Bloomberg
I actually think they may be looking in the right area now. Ocean depth there is such that it may take years to find, though.
This article is a couple of days old but I haven't come across anything else indicating they are favouring the southern arc over the northern arc.