Late October early Nov you might just be lucky at Mosaik, but of course no guarantees. But what they are good at nowadays is moving long-term bookings around to accommodate late enquiries. I always book what is described as a Prestige Studio with balcony, but haven't actually stayed in one for about 6 visits now as they are quite happy to move us into a one-bed or two-bed unit for the same price so they can let my smaller unit to another potential customer they might otherwise lose.
Also if you ask for certain dates but have any leeway at all to move in a night or two earlier or later often that can make the difference as if there is no availability on the specific arrival night you enquire for they will just say 'fully booked' even if the next 13 nights are free they tend not to advise you of this so best to ask in an email if there are any available dates close to your arrival date....that's if you have any leeway.