It's probably just Charley trying to get her name in the papers again.

Shes lying just to get a bit of press attention. BB would never do this.

From Heat World;

We have a little update for you on those quotes from Charley Uchea, claiming that Big Brother have been calling her agent to ask if she’ll go back into the house for the new series. We just had a little chat with our BB contacts, who actually laughed out loud when we told them what she’d been saying. Although Big Brother never confirm or deny rumours about the show, a source close to the action says that Charley’s talking rubbish. Now, that makes a change, doesn’t it? Still, things change very quickly in the world of BB, so we’re not sure we’ll be able to sleep until the series is over and we know for sure that she won’t be popping up…

It's such a low-grade trick to put in former housemates and it never works. Nikki didn't work, Jon Tickle didn't work, Jade didn't work in a huge way. It degrades the show using desperate ploys like that.