If Scotland is a 7-8 night adventure, there really wouldn't be adequate time to go to London IMO. Scotland has more than enough to do in a week. Plus London is kind of far from Edinburgh - you'd spend most of the day on the train unless you flew. I'd bet you'll see a couple of days in Edinburgh, a day in Inverness with a tour of Loch Ness, and then somewhere else - Isle of Skye, Glasgow, Sterling... lots of options. Hopefully they go up the Isle of Skye which is the prettiest area.
I wish they would include more and make it longer. If not, I guess I'll have to add some time on my own, but then I'll be responsible for everything, and that's not as much fun as letting ABD take care of everything.