23/01/2014 at 11:08
Posy, the weather is still mild. I'd take all the plants out for a day with no frost overnight and clean it. Put them all back in next day or later in the day.
24 hrs outside won't do them any harm and not cleaning the GH may cost you dearly later in the year.
The reason now is the time is that any bugs left after cleaning have less chance of multiplying in the colder weather.