My situation was rather different to yours - my ex was the primary carer, but social services forced me to apply for custody (which I was happy to do). Social services had been involved several times previously, but their conclusions were always the kids were not at risk in their mother's care. SS kept telling me to take legal advice, but solicitors said I had no chance of winning custody because all the prior SS reports didn't support removing the kids from their mother. Much to everyone's surprise SS did a u turn overnight, after one more incident.
Initially I was given emergency custody and a prohibited steps order saying that my ex couldn't even have unsupervised contact. Then the S7 report was absolutely damning against my ex, so I won full custody. But bizarely, even though they deemed the kids unsafe in her care, they still advised she have fortnightly unsupervised contact.
Mine was a very non typical case - it's very rare for children to be removed from their mother. We had three hearings (all with different judges), the two male ones were great, but the female judge was clearly predjudiced against me. She hated having to rule against the mother, and was derogarotry to me several times during the hearing. Despite me having done absolutely nothing wrong. Her exact words were 'I have no other choice (than to follow the recomendations of S7 report), my hands are tied'.
I self represented, but I took some professional advice before filing my application. After the emergency hearing, I updated the solicitor that had advised me on the application. It was clear from his comments that he knew the judge quite well, and was on good terms with him. Which is why I wondered if your ex's solicitor is with your judge. I do live in a rural area though, and there's only a couple of family court judges round here.
How long is it until your hearing? Sounds like cafcass are totally on your side, and I think their recommendations will resonate with the judge a lot better for being delivered by phone/video.