Wales/England Child visitation advice needed

[Fabbycass]

Please can someone help.
I’ve rang my solicitor who managed my divorce and got the same answer I got online on citizen advice and both Welsh and English government websites, so I’m hoping someone on here actually has the same situation as me. My ex and I share our 11 daughter, no limited visitation etc, very amicable. Problem is he lives in Cardiff and I’m in England. When lockdown started we agreed that for now he’d just FaceTime her. But weeks dragging on and they both want to see each other. The government advice is the children who are minors can go between both parental homes. It doesn’t however state what if one of those homes is Wales and one is England. And you aren’t allowed to go in or out of wales except in exceptional circumstances, which we believe this is. He tried to come over last night to collect her and was stopped by police just before bridge, questioned (a long queue of cars had been pulled). He explained reasonably to the officer what he was doing but they wouldn’t allow him to continue the journey. Meanwhile bloody cars sailing past over the bridge, including caravans!! We don’t know if this was just bad luck they chose to pull him over, if it was a particularly unhelpful policeman or what, but this doesn’t seem fair and there is nothing that pulls this detail out anywhere for guidance. Any advice or experience most welcome, we have a very upset little girl who wants to see her dad but we’re worried to try again now. Thank you