Legislations are in place to protect all child performers, please view the latest 2014 act here:
http://www.legislation.gov.uk/uksi/2014/3309/contents/made
National Network for Child Employment & Entertainment are the only National organisation solely dedicated to the continual development and implementation of ‘good practice’ issues for children engaged in employment and taking part in public performances.
You can also find more advice on the government website, government guidance; Child performance and activities
https://www.gov.uk/government/publications/child-performance-and-activities-licensing-legislation
Children’s working hours
Children aged 0-4 can perform for 5 hours
Children aged 5-8 can perform for 8 hours
Children aged 9 and over can perform for 9.5 hours
Earliest and latest permitted times at place of rehearsal or performance
Children aged 0-4: 7am – 10 pm
Children aged 5-8: 7am – 11pm
Children aged 9 and over: 7am – 11pm
Maximum total hours of performance or rehearsal
Children aged 0-4: 2 hours
Children aged 5-8: 3 hours
Children aged 9 and over: 5 hours