Hello @Pye,
Welcome to the community boards
You've certainly had a very unpleasant experience and I'm sorry you've had such a negative one with only your 2nd guest.
It's easy to be wise in hindsight, but you let this situation go on far too long unfortunately. By not saying anything to this guest the second the inappropriate behaviour started, your more or less gave him permission to keep going. I see that you've updated your listing to include no extra guests, which is a good idea ( although of course it wont' necessarily prevent people but at least it's clearly stated in your listing.)
It's really hard when you're starting out isn't it? I think the important thing is to not allow yourself to put up with anything that you find unacceptable. For next time ( hopefully there wont' be anything as bad as this) you do need to deal with inappropriate behaviour promptly,.
I'ts often a good idea to do this via messaging so there is a written record of communication.
this is helpful if you need to follow up with airbnb.
In this case, I personally would have been contacting customer support and asking them to cancel this guest. Yes, you would have lost money. but you've lost money on all the excess cleaning you have to do.
Many hosts strongly suggest no having guests longer than 28 days as it can lead to all sorts of issues.
By all means contact airbnb now, but I doubt that you will get much joy - excess cleaning is not something they are generally very helpful about. Still be sure to take plenty of photos.
IN terms of a review I would suggest keeping it very brief and factual and unemotional. eg
I did not enjoy hosting XXXX. He broke many of my house rules, including having extra guests, leaving my front door unlocked. He frequently ignored my requests to monitor such issues. Upon checkout the xxx's room required left substantial cleaning and scrubbing. It was in no way left clean or tidy. I cannot recommend this guest." thumbs down and 1 star for everything.
I'm sure Other hosts will be along soon to offer more advice.
You may also want to tweak your listing further especially in regard to house rules to make it clear what your expectations are. It's not enough to assume guests will leave things neat and tidy. You need to specifically state what you require. It's a good idea to also have this in printed form in a folder in the guests bedroom for their reference. At least that way they can't plead ignorance.
eg guests are expected to empty the rubbish bins in their rooms into the outside bin.
you may find it helpful to read the listings of other experienced hosts and see how they manage things.
It's a long learning curve. Many hosts refined and update their listings as they gain experience.
It does get easier!
Good luck Pye
Regards