Suggestion, Apart from the Legel remedies I would suggest getting the BC to install combination locks, that can have their code changed easily, and issue the code to Only Bona fide tennants, even if one of the holiday makers gets it, it can be simply changed and because you issued it to someone who may have claimed to be a long term tennant or lease holder don’t issue a changed number to the next holiday maker as you had in fact issued it to the ‘tennant’ or ‘leaseholder’. Better still if you see one of the holiday makers move out change it, next holiday make can’t get in!
You need need to put a CCTV camera at the door make sure door is not damaged or wedged open.