child benefit

have made claim for cb for son now living with me ex currently getting son is not going back to mum at all for forseeable future probably never. Ex having made all the I will write and make sure its changed over has in fact told cb she has omly let him go for a cople of weeks and says she can keep cb
how long before
they catch on to her not having any contact
they transfer the benefit to me
Will I get it from date of claim?

appeal against their decision.
notify school, doctors etc of his new residential address

They have not made a decision as such as far as they just quoted that if its temp she can keep for up 2 eight weeks or longer if she gives money to me but that of course means all passported benefits remained with her, PROGRESS though spoke to council and they said yes but only if there was no other person making a claim went back to CB pointed out I had made a claim and that he had been with me continously for more than 8 weeks was ex not claiming fraudulently?Her benefit stopped pending investigation and having pressed about housing issues they are going to fast track this so see u next year? Actually I was surprised the 2nd person I spoke to was not judgemental and was genuinely trying to help.