Jeremy going over for supper that night meant he could give the police the 'fostering' story.
He had supper there frequently, and the foster story conversation, as you call it, most likely took place. Jeremy, a young man, would not have come up with this - he didn´t really care that much about Sheila and her boys, did he? This wouldn´t have entered his mind. I say that that conversation DID take place. It is not strange at all. Colin had a new girlfriend and didn´t want the twins full-time, Sheila was getting too ill to take care of them properly (scizophrenia is a progressive illness). The twins had been in day-foster care earlier. For the life of me, I cannot understand why the anti Bambers keep talking about this as something Jeremy made up. It is stupid!