Zanussi ZX99/5SI Frost free fridge freezer?

I have had this appliance since 21 December 2002. On 19 Jan 06 I came home to find the temperature alarm bleeping and the freezer temperature way up. I tried hitting the internal reset switches to no avail. Cleaned out the radiator vents. Powered off at the mains and restarted. It then proceeded to work perfectly until 21/01/06 when the problem repeated. Re-application of the previous treatment brought no relief this time. I have since had the back off, checked the wiring and given the radiator a thorough clean. The cooling fan function seems to be OK. The compressor is too hot to touch. There seems to be some but insufficient freezer cooling and reasonable fridge cooling.

Any repair suggestions would be welcome.