At the Embassy, Hal is relegated to the Adams Room. John Adams was the first US "minister" (not quite a full-fledged Ambassador) to the Court of St James, re-establishing diplomatic relations between the two countries after the American Revolution. Their embassy was a fairly modest house in Grosvenor Square, and was where Abigail Adams served a feast of sea turtle to an A list of surprised, but delighted, guests from amongst the London diplomatic corps.
At the end of episode two, Marine One is landing on the lawn. Why does the aircraft show British registration letters (G-SEAK).