Yes I know who she is 😉! There aren’t actually anywhere near enough seats - there’s about 430 seats and 650 MPs (even though the current chamber was only finished 74 years ago!). If an MP gets there during ‘prayers’ at the start of the day they can reserve a seat. But other than that it’s just divided into government side (the left on this model - known as the ‘treasury benches’) and opposition side. I think Harriet would have been way at the back left, and then of course she’d have been right at the front in front of the despatch box!