If you consider a replacement, costs between £100 and £200 pounds and lasts 7 to 10 years, I would think that is good value for money especially in the electronics fields. Batteries like the ones in the Meta have a life of 7 to 10 years.
Having a Cat 1 Alarm installed gives me an insurance discount of around £40 a year and I have the alarm in the 600 for 10 years, I think it has more than paid for itself
I have bought brand new Metas for as little as £70.
The Meta 357T -V2 is probably the best Category 1 alarm out there when it is fitted correctly