Monday, August 30, is "Bank Holiday Monday" in England. This is the equivalent of "Labor Day" in the United States (although it is falling the weekend prior to the one in the States), and essentially marks the end of summer with a three day weekend.
This can have several effects. First, many attractions will be open, even when normally closed on Mondays. Second, other places may well be shut, such as many shops and pubs. Third, there can be horrendous traffic on the road, and congestion at holiday areas and attractions.
Just thought you should bear it in mind.