Unless it's a kitsch Wishing well in an English country garden.
You jest but you and others here seem to rule people in and out based on perception ie is this person likely/unlikely to abduct a child?! The difficulty for the CB dunnit brigade is how would he know MM was home alone in the unsecured property? The explanations put forward are unconvincing eg he was tipped off by an OC employee or it was a random burglary and he struck lucky. How would OC employees know the patio door was unsecured since no one could observe this from TB. No one reported a burglary on night of 3rd May so out of all the properties in PDL he just happened to strike lucky in that the one he stumbled across was unsecured with a small sleeping child home alone. Statistical probability of these events happening simultaneously make it implausible imo.
My theory doesn't need to overcome these obstacles. Its based on who knew the Mc's MO not whether I think this person or that person seems likely/unlikely especially when the motive is unknown.
Many seem to want to believe CB dunnit as he's a drifter, petty criminal and sexual deviant. Whereas my suspects appear to be law abiding, middle class and middle aged. But no one knows the motive. Even if the motive was sexual why rule out the latter when they're an unknown quantity?!