Mrs Thatcher is shown sacking Francis Pym from the Cabinet in 1980, this is factually wrong. Pym was moved Defence to Leader of the House in the January 1981 reshuffle he was not sacked. In September 1981 he also became Lord President of the Council. In April 1982 he was promoted by Mrs Thatcher to Foreign Secretary following the resignation of Lord Carrington, he remained in that job until the after the June 1983 General Election.
The whole timing of the Thatcher government's re-shuffle as portrayed here is factually wrong. It didn't take place in 1980 as shown, but was in-fact two reshuffles, one minor one in January 1981 & a second larger re-shuffle in September 1981. There where no mass sackings of Ministers as shown.
Lady Diana Spencer's visit to Balmoral Castle happened one year after the Thatchers' visit, and the Queen was not present at that time. Diana was already familiar with royal ways because she was born into the British nobility and grew up close to the royal family on their Sandringham House, another of Elizabeth II's private homes, where Diana was born in Park House, one of the estate's several houses.