The left hand thread screw (originally securing the chuck) does not fit in the axle adapters in the centre of the drive wheels. What have I done wrong?
Nothing! The 2008 model drills for Scotland should have been identical to the previous years, except for an extra battery. Unfortunately the head of the left hand thread screw is slightly larger and (as you have found out) does not fit in the axle adapters in the centre of the drive wheels. The solution is either to grind half a millimetre off the head of the screw all round, or increase the diameter of the hole in the axle by 1mm.