Much of the confusion with dairy is that there are different issues - there is the issue of allergy, intolerance, and also the unsuitability of dairy due to it's completely different composition to human milk. WRT to allergy, the guidelines have recently changed and it is now recommended that foods that are linked to allergies be introduced earlier - at around 6 months - rather than later. So in terms of allergy, this does apply to dairy too, although certainly not cows' milk at that age - rather the more processed versions, especially yoghurt. However, this is complicated by the other issues which might suggest a delayed introduction. It's pretty confusing, and not something that even highly qualified dieticians all agree on.

I guess at the end of the day all you can do is to trust your instincts!