Just a few more thoughts.
In 1986, Wild Park in Brighton was where they found the remains of the "Babes in the woods," two nine-year-old girls, Nicola Fellows and Karen Hadaway.
Babes in the Wood murders (Brighton) Wikipedia
As I have said earlier, I grew up and lived throughout my young adult years 20 miles from Brighton. It was somewhere teenagers, and young adults go for days or nights out; it did (I'm not sure now as I left England 15 years ago) have a vibrant nightlife.
Everyone from my town knew about Wild Park; you didn't go there, and even locals didn't. If the same attitudes are around today, it would be a good place for them to hide out because of this.
Also, Brighton is one of England's most cosmopolitan and alternative lifestyle places. As I mentioned in previous posts, having an acquaintance or two who live in Brighton is almost a rite of passage. If they wanted to find someone to look after the baby, whether for an hour to go shopping or a more permanent situation, they would find the kind of person to do that in Brighton. CM was a student, and as a student, she would have student acquaintances. These people would be millennials; this article shows a survey result that Brighton is the second most desirable place for young people.
Where do young Brits want to live? Mortgage Introducer
From the article:
"After London, the buzzing seaside resort of Brighton was preferred by 18.8% of younger people, followed closely by the UK’s second-largest city, Birmingham, at 18.3%. Picturesque Edinburgh (17.5%) and Bath (17.2%) also made it to the top five dream locations of the younger generations."
It wouldn't surprise me if CM had contacts in Brighton, or failing that, she knew she could lay low and not stand out too much.
JMO, IMO