Hi Inchy,
As far as I can see, there are Heathrow stage 1 dates available for the 25/09/09 for which I am booked for. I was initially confirmed for the 09/10/09 stage 1 @ Heathrow but updated it by just visiting the interview link and realising I could still do it two weeks early!
Have a look and go for that if you want (you may want to do that asap b4 that also disappears!).