Thank you all. I shall give the newspaper a go then, and like you say it's free too!
We've always used sawdust, then I changed to megazob for a while, then went back to sawdust again. Probably just for convience really, as they sell it at our local pet shop. Probably not good at all for buns, and Bramble already has respiratory problems, so this should be much better. OH was complaining last night though, that it isn't easy to put newspaper in a round litter tray! Bungee is currently using a round washing up bowl, as her tray blew off the top of her run whilst we were cleaning her out and shattered! Must get her a new one.