N/S front tyre wearing on outside edge

[Chrispy]

Possibly - assuming your tyres are non directional.
Apparently the reason why these cars tend to wear there is the sheer weight of the thing leaning on the N/S front on roundabouts etc. Apparently you can dial in a bit of camber with shortened top arms so that the outer shoulder takes less of an uneven kicking on such bends but when driving in a straight line they would ride ever so slightly more so on the inner shoulder. This of course flattens when cornering.
The rears seem to do this as standard but the rear camber can be adjusted easily. The front not so.
Excess toe will also not help, which I had in spades I think.

[charlie_bendall]

I wondered that but cant see any directional arrow on the tyres. Bridgestone duellers on a 2012 40d.

[Chrispy]

I think the Duellers are OK to do this on. I have the same tyres.