I find it a problem that when one takes matters to mediation/CTTT that all their details are included in the forms. And that the forms ae then distributed to everyone. Then you find a situation like this, where lubs is just looking for clarification and something to be done, being harassed by other owners. I have a friend who has a case which is now before the CTTT. He had no idea that his details would be sent to all until he was contacted by another owner. Fortunately in this case it was in support of his plight.
From what I have learnt from flat chat, if these stairs have always been there, and the OC hasn’t had a problem with their existence before they needed maintenance, and there is no special by law or exclusive use by law stating they are the responsibility of the owner, then one would reasonably think that they would be the responsibility of the OC. And if such special by laws existing these would have been pointed out during the purchase process surely.
As for the phone calls, let your answering machine take the calls. Perhaps they will leave a message that you can use as evidence of harrassment should this behavior continue. I have been fortunate enough to have neighbours who self incriminate. It’s like winning lotto.