Anti-Welsh Slurs in English Schools

I recently moved to England to begin my studies and continued my work as a cover supervisor (supply teacher) as a part-time job.

Working in an English school (this is my first and only school in England so far) I’ve been referrer to as a ‘sheep ***’ on a few occasions.

Personally, am I offended? No, lol. But am I shocked how open kids (13-16) are about saying it? Yes.

I understand banter but I am not having banter with these kids, they are just shouting it out to make their friends laugh. Once again, not offended but I am shocked.

Has anyone else experienced something similar being in England?