I believe the land lord is too demanding, the letting business is going down 5euro/hour (in relation to the cost of property, not letting, i heared that on radio other day), I have known 3-4 of my friend that they paid on 1 month advance and got two month rent free,
again this is based on case to case and situation to situation, location to location,
personally you have to make a decision but the demand is too high, so he is taking six month rent?? too much, i would renegotiate, i have left 2 property just becuase of this and had few offers without any key money or advance payment,
even though you decide to pay, make it on lease and get it ink'd