Perhaps Tess has to use the facilities? I know you don't want her to get in the habit of going out for a pee at 2am but...Duncan used to do this, wake me up at 3 or 4 am to go out but would go back to bed if I ignored him. Sounds like she just wants attention...How old is she now? Teaching her the "quiet" command would certainly work also. I think it's a hard command to teach and for them to learn and am currently working on it with Duncan, but perhaps others will be able to help....