I bought some the other weekend as it happens, as found a very local farm shop on the fitch resellers page!
Did a partial clean of pixel and Inch so they have a mix of shavings, hay and fitch. It seems to have confused them somewhat as they have now stopped sleeping in their house and are now sleeping in an open nest
Otherwise they seem very happy with it.
We also tried it in the bottom of the Chinchilla tray, but as it's quite chunky they were able to grab it and pull it up in to their cage. Not that they did anything with it once they pulled it up, but it made a bit of a mess. I'm hoping they were just curious and once they realize it's not treats they will leave it alone and we can use one bedding for all the little ones. We don't have the storage space for multiple bales around the house!