Provided I entered the details correctly consumer recommends a heatpump of approx 1kw output - I am not sure that they produce them at such a low rate. (I have assumed insulated room)
Uninsulated they recommend 2.2 kw
Yes a fan heater would circulate the heat more freely - although you can buy oil heaters with fans, also I would imagine that once the room is heated there would be minimal need to distribute the heat.
I am interested in what you decide. My garage is currently being built, and one of the first things I will do is build a fish room and plan to heat this. I am not sure which way I will go with heating, I was thinking that I would heat two large tanks with aquarium heaters and hoped that the room would be insulated enough to maintain heat around 2 degrees lower than the tank heating.