I work in children and we do 10 minute sleep check on children whilst they are sleeping. Is there a recommended age to stop this process?

Sleep & Rest Policy is a regulatory issue, which is supported by Red Nose.
Please see the following information from ACECQA in relation with Supervision of sleeping children.(P3)
Children sleeping and resting will always be adequately supervised so that educators can supervise children’s safety and wellbeing. Educators will be able to visually check the child’s sleeping position, breathing and the colour of the child’s lips and skin, body temperature, head position, airway and the child’s head and face, ensuring they remain uncovered.
https://www.acecqa.gov.au/sites/default/files/2023-07/PolicyGuidelines_Sleep&RestForChildren;_July.pdf

Also, see latest notification from ACECQA, including new requirements from Oct 2023.
https://www.acecqa.gov.au/resources/supporting-materials/infosheet/safe-sleep-and-rest-practices#Fur