Thanks for the information.
We will be staying at the County Hall Travel Inn and breakfast isn't included. However, I have been told that there is a coffee shop right across the street from the Marriot that has good bagels and coffee, so for us that would suffice for breakfast. We would probably only do one big meal a day, but with a seven year old we won't be going anywhere posh. Lunch for us would hopefully be a sandwich or fish and chips or something of the sort. I am sure we will hit either Rainforest Cafe or the Hard Rock Cafe once, but otherwise just regular food.
Would it benefit us to eat our big meal in the middle of the day? Do Londoners tend to eat later? We typically like breakfast at 8:30, lunch at noon and dinner around 5:30/6:00.
I followed the links, but I still wasn't able to get a good feel for how much we need to budget. But the links were nice to see, thanks.