Lease Break Clause Interpretation and Advice Needed

I'm a residential landlord with a 5-year AST that includes a break clause. My tenant wants to exit early at the 2.5 year mark and claims the clause allows this, but I'm not convinced the wording supports their interpretation. The lease was drafted several years ago and I need clarity on whether they can actually break it, and what my obligations are if they can. I also need to understand any financial implications. I'd prefer straightforward advice rather than lengthy documentation, though I may need a letter if things escalate. This isn't urgent but I'd like it resolved within the next 3 weeks.