suspect Abduction

there is a child where family court proceeding are ongoing

mother has taken the child on holiday on 2nd of july saying they will be back 30th July, fathers weekly video calls came to a halt during this time and email from mothers solicitor said they will resume upon their return, To date father has made calls but no one answers, father suspects their child has been out of the country for more than 28 days. Father currenty has joint parental responsibility with the mother.

can the father file a police report against the mother for abduction?

are there any likely ramifications for the mother if this is the case or is there likely to be no action at all?

any valid breaches of UK children acts?