Pumpy,
I knows its difficult, but you gotta get the fridge right b4 U put the fermentor in there (with wort). U can put the fermentor in there if U want, with just water, and the temp changes won't be so fast.
Mate, what is the current prob? I'm sure it's not insurmountable.
My job is troubleshooting IT. How much harder can fridge troubleshooting be?
Save your sanity and reply soon.
Seth