Yes you will be able to do it yourself make sure you have the alarm code as it will sound as you open the panel. If you can find a alarm suppliers you will get one for £12.00 ish + VAT or
£23.99 XG74R 2.1Ah L/Acid Bat 12V
http://www.maplin.co.uk/module.aspx?ModuleNo=27088&doy=8m2
Hope this helps
Stu
February 2008