Looks like a well unerstood problem. If you had done a Google search for worcester 24cdi no hot water, you'd have found these:
http://www.newtonnet.co.uk/house/boiler/
http://www.diynot.com/diy/threads/worcester-24cdi-boiler-no-hot-water-but-cent-heating-works.50177/
http://www.boilerguide.co.uk/forum/boiler-central-heating-questions/worcester-24cdi-hot-water-issue-216/
Anon
August 2016