Graham Cumming from Edexcel recently emailed people on his distribution list and said
"All mock papers for 2540/2544 and 1380/2381 are all on the website now, although in many instances strangely labelled and on odd pages. We'll be tidying that up and adding the missing ones soon but if you can't wait, go to
http://www.edexcel.org.uk/quals/gcse/maths/lm/ab/
http://www.edexcel.org.uk/quals/gcse/maths/lin-new/ma-new/
http://www.edexcel.org.uk/quals/gcse/maths/mod-new/mb-new/
and look toward the bottom of the page in each case - every file is marked as "new" for the time being."
So I guess they're still being sorted out...