This was in thetford tesco. So maybe only local but worth a try if you are going to your store.
Provides early warning of the presence of CO in your home through alarm and LED display
An internal power pack will power the alarm for 6 years in normal operating conditions, so there's no need to replace any batteries
A test & reset button makes weekly testing easy
It's portable so can be taken on holiday or installed within the home
Automatic self diagnostic check
Triple LED display shows power, fault and alarm
An anti-tamper bracket with sliding tab is available at extra cost ensuring the product remains affixed to the wall
Ideal for homeowners, social landlords and utilities
Kitemark certified to quality standard BS EN 50291-2001.