Our yard employs a mobile livery service. It is an equestrian centre that offers the service. From speaking to the girls who come up, they are extremely busy, so may be worth your while if there is a market for it in your area.
It's possible they have already sold the horse or changed their minds about selling. If the horse is still up for sale, they probably would have contacted you by now, unless they are on holiday or something. Personally I would move on.
Nice to see a positive thread :)
I am on a small yard too, mostly full livery, but I am DIY. All the people are so genuine and kind, truly the best yard I have ever been on. Can't think of a bad word to say about the yard or the people.