Hi Wayne.
I feel your pain! I have exactly the same problem..
I have considered the obvious cuases:
1. Underinflation (I check them quite regularly, and use Citroen guides to pressures)
2. Tracking (wheels were aligned when tyres were fitted)
3. Driving style (I do give the car some stick round corners, but not as much as some, and no real wheelspinning or burnouts)
Heres the evidence..
The inside of thw tyre still has plenty of tread..
I've had a word with the Saxo lads and the general consensus seems to be: camber/castor/tracking.
Hard driving would also do the damage.. BUT
NOT underinflation, as that would wear both shoulders. Do you agree?
They seem to think that even set up very well, this problem will still occur..
Don't know wether to bite the bullet and go to some suspension specialists, keep shelling out for new tyres; or sacrafice grip levels for hard compounds.