Def leave him to sleep Oi; we've been known to put DS down to sleep in his day clothes and the nappy he was wearing (as long as it wasn't poopy and had gone on fairly recently, obviously!) if he'd passed out. Just have a bottle of milk to hand for about 1am...I see that SAHM has already beat me to it!
My poor little boy- he had all the disruption of Xmas (a week away sleeping in three different homes on top of ours) followed by croup, and then the top molars coming through. Today I noticed the bloody bottom pair had just cut too, so poor little sod's had all four come through in the space of a fortnight!
He had dribble burns on his chin 
But is now mega jaws with 12 teeth 
I know what you mean Plu, I worry about that too; I got to grow up running wild (in a kid's mud pie way, not crack pipes iyswim!) in both the very rural countryside and the middle of Manchester.
My siblings however... they live in a teeny tiny village in Hertfordshire and my little sis wasn't allowed to go to the corner shop 50 yards away on her own up to the age of 11...and then had to get two buses on her own for secondary school. Definitely want to get DS running about as much as poss.
And LMF, I am almost as delighted by your iPhone as I am by the news Octoboy's pox is clearing, that's great!
Oh, do not mention carpets, mess, and the lack of roof support joints for our loft "conversion", ha...