I would recomend full sun and plenty of water for this plant in the Uk.
I'm not sure about the brown dust though, is there any grain being harvested near you at the moment, I've seen some combine harvesters creating a lot of dust in the drought stricken area near me.
There are several types of banana plant claimed to be root hardy, with frost protection in the UK, I have a Japanese variety (Musa basjoo) Which I've had growing in the ground for about 4 years now and its reached about 16ft high with some leaves about 6ft long and a clump of 7 stems. I cover the whole thing with straw in the winter to keep the worst of the frost off, I guess you could take yours indoors in the winter, if you want to keep it in a pot.
I dont feed mine but occaisionally put a mulch of horse manure around the base, maybe some tomato feed may perk yours up ? Good Luck Tbird+