They hate being moved. Buds fall off if you move them. Make sure you don't overfeed. Mine does not like to dry out but do not over water.

I was told that to get Christmas cactus to bloom for Christmas you must not give it any water during July or August. I tried it and found that it flowered really well - in November, so you may want to adjust its "drought period" a bit.

It also needs at least 14 hours of unbroken darkness each night, starting 3-4 months before you want it to bloom, and going until buds are visible--usually about 9 weeks.

Mine didn't get long periods of darkness on the kitchen windowsill...

May have had enough darkness, anyway, Beattie, especially if the curtains were closed behind it and there were no porch lights outside. Christmas Cactus isn't as sensitive as Poinsettia, which will stop forming buds with only a flash of light in the night. I wouldn't have stopped the water that long, but even houseplants need watering more often here in the desert.