Usually Comreg send a letter to site owners informing them of the fines they face. This has been the case in recent years in relation to the FM pirates. This why there are few FM pirates on air these days.
Both these SW stations were, I believe, in the same part of the spectrum which makes me believe it was frequency related. Perhaps on or close to distress frequencies or frequencies reserved for something.
The chances are that Comreg were instructed, maybe by the ITU, to remove these transmitters from the air. Hence the lack of a warning letter.
I don't think it was a case of Comreg having nothing better to do.