We recently bought a Bichon Frise from the RSPCA, she is only two years old. She is such a perfect dog in all ways, the only problem we have is that she fouls at night and when she is left on her own for as little as ten minutes. We have never caught her at it and because of that we have never told her off. Can anyone help us with this problem, her previous owners gave her up because of her fouling in the house. We wont give up on her because she is such a lovely dog, but it does get annoying when she does the deed and we have clearly left the back door open!? Mark

Maybe's she not realising the door is open for her to go outside to do her business??

You could try getting her a dog crate, with her blankets in one side and papers on the other. Dogs rarely foul in their own beds. So this would be useful to prevent mess on floors overnight.
Even during the day, if you need to leave her, even for a toilet visit yourself ;) , then put her in crate. This is what I am doing with my Basset baby. It's for his safety too, and also to keep my carpets clean.
During the day, make sure you take her out regularly, but stay with her so you're sure she's done..after naps, after play, after food etc and praise her to the heavens when she has done the deed, or reward with a small treat You'll soon get to learn your dogs body clock for needing to go.

I couldn't do without dog crate's. They really are excellent. And also the dog learns that this is their own little private home. I drape a sheet over my 2 crate's, just to make it more secluded inside, and both my dogs love them.
Hope this has helped in some way, and good luck. Don't give up on her. She just needs to be taught where is allowed to do her business. And from the sounds of it, you have a gorgeous dog.
Steph xx