Whilst on an early morning blat this morning, I had to do a three point turn and heard a clunk from the steering when on full lock. I then found the steering wheel was off centre, although the car itself was behaving itself fine - inspection of all bolts relevant to the steering system showed the reference marks still lining up. On inspection in the garage, I found the joint between upper and lower parts of the column was switching between two positions when a decent amount of torque is applied. Disassembling the joint, I can feel witness marks in the flat on the lower column where the grub screw had engaged, but there is no obvious damage as such. The clamping bolts were in their original position, at least based on the reference marks on the heads. I assume that over time, there has just been a bit of plastic deformation and the grub screw just needs readjusting and tightening. My plan was just to adjust the grub screw to have more contact force on the flat and then reassemble everything with some loctite on the bolts. I was a bit bemused to find such an agricultural connection between the parts of the column, but there you go. Has anyone had this problem before?