Thankyou all for the advice!
Well, we have done it. Since I wrote the original post, DD has been dry and out of nappies!! Not one accident (knock on wood!!). I have put a garbage bag cut in half on her bed, under a blanket and mattress protector. We go to the toilet before she goes to bed and I try to limit her fluids after about 6pm-ish. I can't believe she has been so easy to toilet train. She has practically done it all herself! I'm so proud of her, and she is SO proud of herself!!

DS on the other hand, is proving a little more difficult, lol!