I find FSID's position on co-sleeping a little difficult to understand. They don't actually come out and advise directly against bedsharing, but a lot of their wording ('there are dangers in bedsharing',
'it's especially dangerous to bedshare if you are a smoker etc.'), imply that they consider it dangerous.
We have ds2 in a bedside cot. I wouldn't sleep a wink if he were in a separate room. In fact, ds1 still sleeps in with us as well (in his own cotbed), and I know I'll be rather when he finally decides to move into the bedthat's waiting for him in his own room.
We have a routine going whereby dh rests/sleeps on the sofa for the first couple of hours of the night with ds2 (in his Moses basket) right next to him - and he says ds2 unfailingly wakes up and becomes unsettled if he gets up. I feel it's entirely plausible that the proximity of the parent/s aomehow regulates the baby's sleep patterns and breathing.