Having quickly looked through the video it looks like a 9kwh pump will do the trick.
As I said the other day 9-11kWh based on floor area alone and a little knowledge ?
That said they are only guestimates as too small it will work its bollocks off and too big will cycle and inefficient!
However I would not install a heapump without carring out proper heatloss calculation as there are too mny variable.