I was a nanny for a 13 mos old, 3.5 yr old, and 5 yr old (when I started). I worked 8-5, M-W, and F 8-1245ish (whenever I dropped the older two at preschool). Mom was mostly WAH in her office, but occassionally gone.
Mom didn't care too much about tv...I did. The deal I made with the kids was that they could watch on Fridays from the time they finished lunch until we left for preschool. So, about a half an hour/week (the youngest was at kindermusik w/mom at that time). VERY occassionally, if I was asked to stay later than 5 (which was about 1x a week), I'd let them watch a video after they finished dinner (maybe once a month). It was usually more trouble than it was worth, IRT agreeing on a video.
Let's see...the older two were in preschool M and W from 1245-300pm. The youngest usually napped during most of this time. Other than that, yeah, I played with/taught/cared for them, tv off. Now, I might have been playing with the baby while the older two played together, or we might be doing something all together, or I might be inside with the baby while the older two played outside. I pretty much interacted with them constantly - if not directly, then observing. I would take a break to pee or something (with the baby, generally), or tell them, "Hey, I've got to load the lunch dishes, and clean up the kitchen," and they'd amuse themselves for 10 minutes. Especially once I was heavily pregnant, I *would* say, "I need to eat. You may have a snack with me, or you can go play by yourselves, but *I* need to sit down for ten minutes, and eat a sandwich."
I don't think nannies are workhorses, and I don't think they should be "on" 9 hours straight, but I do think a good nanny is able to discern when a good time for breaks is, when is a good opportunity to do XYZ, and how to regulate tv/media consumption.
I'd look into a new nanny, personally...