I apologise for this, but I would suggest not following the instructions for this kit
The instructions for brewferm christmas say that it should be bottled at 1020. However, my kit was at 1020 after about 48 hours of fermenting. Undeterred, (I am a stickler for following instructions) i bottled the kit after the short ferment.
The brew was done about this time last year. I had a sample in september/october and it wasn't nice. However, by the time christmas came, they were much nicer and had come into condition.
Bottlign early resulted in an awful lot of sediment in each bottle, however. i am nto sure, but i think there may have been a slight off taste from this. If I were you, I would ferment to 1020 as the instructions say, then rack to another fv. If you have a fridge spare, perhaps you could then chill to try and drop as much yeast out as possible, and then bottle it.
I am nto an expert though, this is just a humble suggestion.
Be warned, this kit takes an awful long time to come into condition, so get brew on now for christmas drinking.