As I understand it, the new control tower being constructed just behind the Royal Suite is the reason for the timely closure of 23 for this winters gales.... but the tower is only being built there, it will not stay there. It is destined for the T5 site near the fire station, just with the T5 works underway the re is nowhere there to erect it. I understand that it is to be towed across to T5 in March sometime, hence the late March expiry of the NOTAM - should be interesting!
At the same time they are constructing 2 new parking positions opposite the old Deltas - I presume that they will not be used for boarding, just parking, as otherwise pax coaches would need to cross active taxiways, still who knows?
You may be right in that 23 may not be used again, certainly recent practice is that it is used as little as possible because of the disruption it causes (loss of old W stands at end of 23, towing operations from maintenance base to all terminals, taxiing to/from T4, etc). As per W stands, the new stands ooposite the Deltas would be out of service during any 23 operations. I guesss that they are taking the opportunity of 23 being out of service to build those new stands - forward planning!