Hi @Rosie118 I hope you are well.
You won't find a company who will offer a one time meet and greet, it just wouldn't make financial or logistical sense for them.
Could you reach out to some local hosts in your area to see if they could help you if it's a one off? (Local facebook group, or contact some hosts by doing a search as a guest, put an advert on AirTasker etc)
Or a local friend/family member or even your cleaner?
Otherwise maybe think about a lockbox that you can secure somewhere outside the house so guests could let themselves in.
I use one when I am not around, and attach it to a discreet pipe where it can't be seen easily, and I give guests detailed instructions and pictures to find it!