this dry cleaners is excited because it's 25 years old and is having lots of 25 related bargains.

however, i'm a bit confused, as it proclaims 25% off, but also £25. And it seems to be suggesting they've got a selection of services including 25 hours, 25 days, 25 weeks, 25 months, 25 years. I can see the 25 hours service being popular (although plenty of other places do cleaning in fewer hours), but a 25 week service ? why ?