Well I have paid a small deposit over the phone, and they are bringing the car to me. They have agreed that if I approve the car on arrival, then I hand over the bankers draft; if for any reason I am unhappy, they take it away, and refund the deposit. So lets see what happens!
Thanks for the advice everyone.
I have been told the same consistent story by about 6 dealerships now, that the new car market has died a death, and used cars are selling very quickly - they all seem to have particularily limited stocks of IS250s, such that prices on these have actually started to increase. As I have been looking for a little while, this price increase does seem to be true over the last few weeks (but not months...cars are still cheaper now than they were last quarter 2008)