Center Parcs Safety Leaflet:
// Supervision in Pools
The following supervision ratio operates throughout most areas of the pool:
• Under 4 years: One child per responsible person of at least 16 years of age
• 4 to 7 years: Two children per responsible person
Regardless of age, weak or non-swimmers should be supervised at all time, by an adult swimmer in close contact. Parties not being supervised to these standards or who are not supervising their children responsibly may be asked to leave the pool. //
https://www.centerparcs.co.uk/content/dam/centerparcs/information/uk-villages-safety-guide.pdf
Presumably, Tommy was supervising the Bar area.