Battery powered clock (faulty) (Lyppard Grange WR4)

I have this clock to pass on to someone. It is a big clock, has a dismeter of 16 inches (40cm) but when you put a new battery in, it only lasts 3 weeks. It might just need some tinkering with. It is only 6 months old. It is an RF clock, so rests itself automatically when the clocks go forward an hour.