As I said avoid the twin pack Makita, although a good
deal in itself and get a 18v Impact Driver as the drill/driver will be
not used for much of the time.

Most 12-14.4V impact drivers seem to have max torques around 130-140
Nm. This is more than sufficient to drive 6*100mm screws into
softwood, undrilled. The bulkier, heavier and higher voltage models
are probably more appropriate to driving hex head fixings with a 1/2"
drive socket.

Although I agree a cordless drill gets used less with an impact driver
around, it's still very useful when working with a hardwood to have
the drill bit mounted in it and not to be frequently switching bits on
the impact driver.