Thank you for your question.
I've put your measurements through our stove calculator https://www.directstoves.com/stove-calculator which gives a minimum stove output for your room as 3.33kW.
You should be fine with the Arundel in this room, but we wouldn't use anything with a higher output for a room of this size.
It's a good choice and one of our best sellers.
Hope this helps?