Depends on what is in the lease.
Essentially they own the building itself and the ground it stands on and will have certain rights and responsibilities towards it and the other people who live in the building who may be still living there through council housing.
I'd have thought there should have been a s.20 notification of intended works. Some more info here...
http://www.lease-advice.org/s20frame.htm
Have you checked whether any notice was given, whether any notices were put up in communal areas etc... Doublecheck their address records to make sure they have them right for you (unlikely they won't have on a RTB).