Do you have any extras on the alarm ?, if so these consume but 2 days is not right at all.
I have same alarm and can leave 3 weeks no problem, a bit sluggish but starts.
The easy way to tell if ther eis anything else on that fuse is just leave it out and see what doesn't work, certainly without being switched on the ciggy lighter and seats should not consume anything, but if the seat has a dicky switch/relay they consume a hell of a lot over 48 hours, easily enough to flatten the battery.
The alternator could also be flattening the battery even if charging 100% ok, again just disconnect main charge wire(insulate well as direct to battery) to rule it out over the two days.
Is the batt defo ok ?
tabetha