Wasn't it part of the compromis de vente that they needed a mortgage
and so they could pull out if they could prove that they could not get one???
Have they paid a deposit??? If they have and rollocks things up, then you would be able to keep it.
We made offers on the house we are now living in three times and frankly if I had known a couple of things about it, it would have been four times, always reducing incidentally.
And then we bought it, I don't think we had signed anything though, a verbal agreement. And as I said, IF some of the problems we later ended up with, had shown at the time, I would not have hesitated to try to get more money off the price.
When we sold in France they too kept coming back with lower offers, but there you go, that is how it is, think that the last offer we worked out half way between their offer and what we wanted.