Rubbing sound from near side on full lock when parking

[Joey P]

Before buying my 02 1.9 TDI, I did the full lock tests in a car park and heard nothing of obvious concern.

But have since noticed every now and then a sort of slight rubbing noise on full left lock at parking speed. Sounds like it is coming from the front near side, possibly steering column. Does not sound a metallic or harsh noise.
No noise turning when driving at any speed, that I am aware of.

Only thing different from initial tests are the tyre pressures, they were all a little lower than Ford suggested.
I have since set the tyre pressures to where Ford manual suggests they should be - 41 front 38 rear.
And I have a chipping gravel drive.

Any ideas what this noise might be,  or where to start checking!