Hotpoint RZ64N freezer will not cool?

We have recently recomissioned this freezer which has been stored in a garage for the past twelve months and now brought inside. It was left to stand for a couple of hours before starting but 48 hours later tha compressor is running yet the temperature is still at +5C. Have no manual and cannot readily see any tubes which might be blocked (but this is only from a visual non-dismantled inspection). All three lights are on - green mains, amber fast freeze and red warning.

Any ideas?