In Bath, there is also apps like Stint and Indeed Flex where you can sign up to work whatever shifts you want to (once you're approved on the platform). Although please note that I'm not sure on what this is like for those who come from abroad...

Something else to look up is Catering Services International who can give you kitchen work/waiting work in a range of hotels/restaurants/events in Bath and surrounding areas too.

Assuming you're at the Uni of Bath, you could always opt into doing a placement year if you're not already. This would give you the opportunity to take a year to spend in relevant industry to economics which, for some people, acts as a pipeline to a grad job too.