Yes we praise her when she does it outside-neighbours must think we are mad. Usually we ignore it when she has done it inside but i must admit today i put her outside when she did it. She goes to the door when she wants to go into the utility but not when she wants to go outside.
Next-yes she appears agressive when she bites. Once she bit me when i tried to move her away from the guinea pig run that she was chewing.
With regard to walks-it's difficult to know whats best. On this forum i have been advised 5mins walk for each month which is no way enough for my dog (she is a collie) so we do walk her more. She is not over fed as often she will not eat her food for a couple of days (again i have been advised that she will eat when she is hungry). In fact yesterday's meal (its dry food) is still there un touched.