Mr. Mybug compares Branwell Brontë to Thomas Chatterton (1752-1770), an English poet who died of arsenic poisoning in what was possibly a suicide attempt. The poet John Keats wrote an elegiac sonnet to his memory in 1815:
O Chatterton! how very sad thy fate!
Dear child of sorrow - son of misery!
How soon the film of death obscured that eye,
Whence Genius wildly flashed, and high debate.
The Corn Laws were enacted in the early 1800s to limit imports of foreign grain and protect the profits of British farmers. Highly unpopular with ordinary people because they increased the price of bread, the laws were seen to favour the interests of the land-owning classes. They were repealed in 1846 during the Prime Ministership of Sir Robert Peel (1788-1850).
The 'Duke' was the Duke of Wellington (1769-1852), Prime Minister of Britain from 1828 to 1830, and a prominent politician in the House of Lords until his retirement.
Lord Palmerston (1784-1865) was initially Secretary of War, then Foreign Secretary, and eventually Prime Minister from 1855 to 1858, and from 1859 to 1865.
Thomas Carlyle (1795-1881) was a Scottish writer, essayist, and historian. He was brought up in a strictly Calvinist household, but as an adult he rejected his Christian faith. His non-Christian viewpoint and his complex and challenging style of thought made him a popular author with sections of the Victorian reading public.
Although Victorian Vista is a made-up title, a controversial biography of Thomas Carlyle was written by his friend James Anthony Froude (1818-1894) under the title Life of Carlyle. The first volume was published in 1882.
I weep for Adonaïs--he is dead!
Oh, weep for Adonaïs! though our tears
Thaw not the frost which binds so dear a head!
Fitzrovia had a reputation as a favourite haunt of bohemian types, whilst Bloomsbury was made famous by the 'Bloomsbury group', a set of intellectuals and artists whose members included Virginia Woolf, Vanessa Bell, Vita Sackville-West, E.M. Forster and Lytton Strachey.
It is probably members of the Bloomsbury group whom Stella Gibbons has in mind here. Interestingly, the country retreat of the group was Charleston Farmhouse in Sussex (just over the hill perhaps from Cold Comfort Farm!).
'Lions' in this context means 'celebrities'.
The sketches, which were illustrated by George Cruikshank, were first published in book form in 1836.
Hyde Park was an important cruising area for gay men during the 1930s. Mr. Mybug is presumably suggesting that one could not be in Hyde Park for five minutes before either being accosted by a homosexual, or arrested for being a homosexual.
When Cold Comfort Farm was written, homosexual acts were illegal in the United Kingdom, and they remained so until the Sexual Offences Act 1967 decriminalised sexual acts in private between consenting males in England and Wales.
Reggie Oliver, Stella Gibbons's nephew and biographer, reports Stella Gibbons's friend Ida Graves as saying that this scenario was based on a real incident, and that Isobel Powys, the niece of the novelist-brothers John Cowper Powys (1872-1963) and Theodore Francis Powys (1975-1953) was the model for Harriet Belmont.
Oliver also suggests that elements in Cold Comfort Farm parody the work of J.C. Powys.
Isobel Powys married Herbert Marks (who had previously been married to Ida Graves). Marks is generally believed to be the model for Mr Mybug.