They sell a straight center pole for £14 or a curved one for £37ish to support center of cover. Think 3.1m ones come with straight center pole. Can be used for 2.8m ones too... not sure on smaller ones.
nothing hard about putting caravan stores away on your own. and as said by several here that use them, they are stable if you tie them down.
i had one but traded up for a used omnistor 2000. got it for the same price as a used fiamma, but its metal cased and self retracting. it also has the spreader arms (supports) that go from the center out to the ends so no need for additional bars. you can use it throughout its length ie you just lock it to wherever you pull it to so you can have it 2 feet or 8 feet out or anywhere in between. its heavier than a fiamma, but it addresses some of the fiamma issues too.