We used the bassinette attachment of our Bugaboo for the first month before DS moved to the cot, even after that he often had day sleeps in the bassinette, always with the hood down for ample ventilation. We changed over to the seat part when he was 4 months old.

HTH!

PS - Oh I meant to say that we added to the supplied mattress...a mattress protector, sheepskin and fitted sheet. Although I have a feeling that sheepskins are a SIDS risk....but ours was quite thin.