[Closed] What garden office heating

Just about to start using the garden office officially ( its finally finished after some leaks have been eliminated).
Its pretty well insulated, but needs something to provide a bit of warmth in these cold months.
It also gets quite warm in the summer, so may need something to cool it down ( on days where i don't want to just open the doors)
I have a few options

1. Electric Wall mounted heater
2. Electric Infra Red Wall mounted heater
3. Proper aircon unit with wall mounted control unit and external condenser
4. Dyson hot and cold fan.

The room is approx 12m2 so around 1500W heaters should do the job.

Anyone had any experience of the Dyson fans as a primary heat source and are they any good.
Obviously 1 and 2 have no cooling facilities and 3 runs the risk of creating a leak issue if not
installed 100% correctly. I don't want a big unit taking up floorspace.