Don't want to upset your holiday plans, but I'd go along with all of what Stu said BUT the big problem is if your filter fails or worse still, heater jambs on, or even worse than that, the tank cracks.
Maybe you could get in touch with a local school and see if a kid would like to earn some pocket money??
Of course you would have to do some qik training.
Turn the heater off, you won't need it over Xmas. If it locks on you are going to loose your fish, if it burns out, you'd be in the same position as if it was off.
But I'd say go and have a happy holiday, the fish should be fine, if you do as Stu says.
A bonus of that is that the fish will really appreciate your return.
Alan 104