My sister in law is after buying a 2012 Golf Tdi 1.6 blue motion (105 PS) 5 door. It has 16000 miles on the clock and it is being sold by VW Altrincham, Manchester.
It is for sale at £13,500 and comes with a 12 month mechanical warranty.
I have never bought from a main dealer before as my cars are old and cheap

What is the negotiation margin with a main dealer? 10% etc
and
Why is it only a 12 month warranty? I thought it would still be covered by the 3 year warranty.
Thanks
Luke