"I thought CM testified that they planned to find a private foster carer (not randomly) to look after Victoria abroad when she was 6 months old so that they could stay in Britain and fight for the return of her siblings".
She said the plan was to get themselves out of the country and find accommodation, leaving Victoria with someone they would find from Gumtree who would then, after a few months, smuggle Victoria out of the country to join them.
My reading is that she said they'd stay with their baby for three months (so I was wrong to say six months), THEN hand her to a person who would care for her (a person whom she would spend time with as part of the checking out) while she and her husband would be in Britain so they could continue to fight to have their older children returned to them. Then the family would rejoin their youngest child later.
It is not clear whether they intended to travel abroad with the baby in January. Perhaps they intended to travel abroad, but not on the same ferry, meeting up with her after a day or two and then coming back to Britain alone after three months for the custody fight.
One has to bear in mind that these people's lives were not easy, and conditions may have been such that although they understood that a plan should be kept as simple as possible, they were also aware that objective circumstances can dictate that "as simple as possible" is actually quite complicated. She is a fighter, but added to this they were under huge pressure. She has clearly been under pressure before, and survived, but that doesn't mean it didn't get to them. So it is possible the three months plan was formulated only after a quick flight plan failed.
Gumtree can be added to Lidl as a brand reference that's capable of distracting from the most salient points. She said there were many people who would help and when pushed she mentioned Gumtree as one place to look. Presumably she didn't want to say too much about the escape network.
I wouldn't read too much into the Harley Street reference either (another brand). That was in response to a question asking whether she planned to have her daughter registered with the NHS or not. Rhetorically the cross-examining prosecutor was trying to establish an association in the jurors' minds that went CM versus NHS, and NHS good, so CM bad. In response, she mentioned same-day appointments, i.e. "NHS not so good, and don't we all want the best for our children?" Elsewhere in her testimony she mentioned the Post Office scandal. Rhetorically, both the Harley Street reference and the Post Office reference can be filed under contextualisation with a political flavour. In the case of the Post Office, the association, this time coming from the questionee, was "We used to think the PO was good, but things came out about how it was treating quite a large number of people outside of the public view and then its reputation fell down a hole; and many today think the SS are good, but ..."
Emotionally they were probably torn between escaping from the country with their newborn and fighting in Britain to get her siblings back. How this affected planning I don't know, and it didn't necessarily affect it the same way all the way through. Moreover it is obvious that a few things went seriously wrong, as they do even with the best-laid plans.
It seems to me that
1. They wanted to go abroad with their baby.
2. They wanted to come back for a custody fight, during which they wouldn't disclose that they'd had another child;
3. They probably envisaged living with all their children outside of Britain.
4. The "Harley Street" reference shouldn't be given too much weight, except as a reminder that both the cross-examining barrister and the defendant were acutely aware, ISTM, that what matters when you ask or say stuff in a witness questioning session at a crown court trial, whichever side of the rail you are on, is
what effect it has on the jury.
5. Barristers are taught that ideally you shouldn't ask a question in cross-examination that you don't know the answer to. Just from an objective POV, CM performed extremely well as a witness, because she didn't let the crown counsel get away with that. In other words, she didn't let him stay in control. That is presumably why he kept her in the box for so long, because she was smashing him all over the ring and he had to keep trying to plant a right hook or two. I expected CM to be a good witness as soon as early on - in examination-in-chief IIRC - she said that she felt guilty about her daughter's death. She felt guilty. That's what she said. Cue attention spike and the hearing of the message "There's a different viewpoint here from the prosecution's one". This is WAY beyond "I didn't punch him. Sometimes I get angry and shout, yeah, but I would never hit someone over the head with a spanner. I'm not that sort of bloke" - the kind of boring stuff heard in criminal trials every day.
JMO