As shady said, you probably wouldn't have got a discount if you asked "Would it be possible for me to get a discount?" You should have said "How much of a discount are you going to give me?"
My preferred approach is not - "how much of a discount will you offer me" - its "I think the property is worth X". Ill give you X. If you want to sell me to me fine, if not Ill buy elsewhere.
You need to frame the negotiations in terms of what you think the property is worth - not in terms of whatever random number they have written on their price list.