Steering offset
 

Got in the car to go to work last night, steering slightly offset to the left.
Car now pulls to the left.
There's been some knocking from the front for a bit which I put down to the tie rods (got some on the way). Anyway, it drove ok in the morning and I haven't hit anything so it seems a bush or joint has finally given up the ghost.
I jacked all 4 corners and checked over the car with the wheels on and nothing seems loose. Only problem I found was the rear offside tyre was down to 24psi. Pumped this up but the steering offset and pulling is the same.
Any ideas or normal wear points for when I get chance to have a good look over the weekend?
Could the anti-roll tie bars cause this (mine are knackered on the front).
Help?? :notworthy