My first thought is that a wheel bearing has gone (due to the knock) causing lateral movement of the hub in relation to the disc, maybe only under certain circumstances like cornering when its under lateral load. Id be surprised if that would account for it on both wheels (if it is both). If the dealer found the bent steering arm without being told about the knock they are not doing to badly so id hope the checked the bearing, however as I hinted it may not be evident (e.g. a knackered bering will show if you jack the car and try to move the wheel laterally, but it not 100% Guaranteed to show up an iffy bearing)
Its also worth taking the wheels of an looking on the inside to make sure that the alloy is not deformed and tapping the possibly knocking it onto the disc. or anythign else like a splash shield etc (not sure hoe the freelander 2 gubbins work). You should see scoring on the inside if there has been contact.
The above a still a bit surprising as assuming the pads are fresh id hope that the friction material would mot up an lateral movement and you wont see scoring as such, more just uneven ware or corroded patched where there is no contact to knock off the rust etc.
Thats my thoughts,
