It looks that he did get a letter from BD.
If that's really the case, then I personally think he should come out apologize and pay double or more of the penalty.
Very ma fan ga .. when you want to do some construction in HK ( or even here ) suppose need to send many application, then wait for approval, and once it is done, they need to check again ...
Well, 僭建 is very common in HK .. here too ... not too sure about HK, but here, most people do that because of tax ...
(dumb me, reported everything we have done in our basement .. since then, our p. tax has rised so much!!)