Tilt and turn uPVC windows drafty....help!

[angularbanjo]

Hi, we have 2 uPVC tilt and turn double glased windows (about 15 years old, pretty bog standard I think) both of which feel drafty when closed down the hinge side (top to bottom). I'm guessing wind is somehow getting past the black rubber seal on the sash of the window which is meant to be squeezed to form a good seal between the sash and the frame when the window is shut. I've cleaned the hinges and the various gaps and I was going to lubricate the inner and outer seals with rubber conditioner tomorrow. Thing is, they (the seals) look in really good nick. Do they just go a bit brittle over time?
Any thoughts or experiences of the same problem would be much appreciated.

I've enclosed a picture of the whole window and its drafty on the right hand side just before the curtain, also one of the 2 seals, outer one on the frame and inner one on the sash.

Cheers
Steve

 

[crank39]

Put an allen key into the keeps on the frame show in picture 2 and turn, this tilts the keep so when the lock slides into it will give you greater compression

 

[angularbanjo]

Put an allen key into the keeps on the frame show in picture 2 and turn, this tilts the keep so when the lock slides into it will give you greater compression

I'll do that tomorrow, many thanks.