Good boxing gyms for 20+ year olds?

Can anybody recommend a good boxing gym what they have been to this or last year? Im from Rotherham but there’s not all that much to choose from over here and the good boxing gym only seems to want to bother with rising amateurs from kids to teens. I’ve been to 26rr before and the gym and facilities are great but it has more of a boxercise/fitness feel to it rather than boxing. I’m really wanting to learn techniques and train really hard getting plenty of sparring and pad work in