Just giving you an update - I've just got my first cycle today having not had one since my son was born. So even though my son has been co-sleeping with us and waking numerous times throughout the night - fertility can happen! Yay!
I've also been putting him to sleep on the floor next to our bed before his 1st night waking, which just removes him from the smell of the boob for a bit - thus giving him just a tad longer sleep. He then comes into bed with me