Basically "I'm interested in the AW3418DW, could you look at what's the best price please?" If they come back with a high first offer, say £990 or something, I just call it a day. If it's something half good, I then ask for the second hit. Like others have said, I've only ever had two spins of the wheel.
Lowest I've had before was £935 (a few others have had the same). Today was the first below that.
I think if I had not read the £830/850 posts I'd have taken them at the £913. The minds a strange thing.....