Hospitality is always available in sports stadiums, just sign up to an agency!
As a student I worked at Cricket Test Matches, Horse Racing, Football Stadiums. Rugby, Tennis and Golf clubs, Galas, Civic Functions, Award Ceremonies, Company events, Weddings etc…. they also can find chambermaid work too!
There are non caring jobs in care homes available to under 18s such as porters, cleaners and kitchen porters.
Fast food restaurants are always recruiting new staff too!
Shoe shops and uniform shops take on extra staff during the summer holidays as it’s their peak season.
I have had a job continuously since the age of 14 - weekends and school holidays while at school and sixth form, throughout university at evenings and weekends, and after graduation! After graduation I have never been unemployed either!
You just need to be creative and think positively about using agencies to find you hospitality work. Just walking up and down a local high street won’t give you many options. Cast your net more widely!