Assuming the artex is on the ceiling only you should be able to remove the wall without disturbing the ceiling. Whatever you see on TV you should always be wearing a mask when doing dusty operations.
If the ceilings in both rooms are in the same plane, you may be able to bodge them, pulling them down will have a better long term result.
It may well be that the artex has embedded white asbestos, however, we breath in asbestos every day as it is in the air all over the world and it does us no harm.
Provided you do not use power tools on artex, the asbestos will remain embedded. You should be able to pull the plasterboard down without too much trouble.
As mentioned elsewhere do use a decent dust mask, 3M have a range 2125 that come in different sizes and you will be able to buy one with removable changeable filters that will last though out the job.
If the boiler is working keep it, new ones cost the earth.