We have the exact same problem. Have had an appliance engineer out twice(independant not hotpoint). First time he advised turning up thermostat to 4- 5 and defrosted the freezer for us with hairdryer - this didn't work. 2nd time he fitted new thermostat this hasn't worked either. On point of buyng another. Noticed the comments on "Beko CD543f just out of guarantee". Might try this as last resort.
Helen Weeks, October 2008