I've been looking into some post-1918 British and Irish possible events etc.
I'm not sure if you've got these at all, but, doesn't hurt to suggest or post up. Hope these help a little for some British political flavour events.
UK
1919 - Government of India Act, provided dual government in India
1921 - Imperial Conference , at the conference the Canadians successfully persauded the UK not to renew its Japanese alliance, though Australia fought for Britian to renew it
19th October 1922 - Carlton Club Rebellion, Conservative Party votes to leave the coalition with Lloyd George's Liberal Party and fight the next election as the Conservatives, not as a coaliton. End of the Coalition
1923 - Liberal Reunification and revival, the Liberal Party's decline was swayed for a moment when Lloyd George and Asquith joined together an dreunified the party under the Free Trade banner for the 1923 election, which Baldwin (Cons) stated in favour of Protectionsim.
1926 - Imperial Conference, introduced Balfour Declaration of 1926 with established the idea that the dominions were no subordinate to the UK and were equal to the UK!
May 1926 - TUC General Strike, General strike across Britain
March 1929 - Liberal 'Orange Book', this pamphlet was Lloyd Georges promise to combat unemployment, with the backing of J.M. Keynes.
December 11th 1931 - Statute of Westminster, established a status of legislative equality between the self-governing dominions of the British Empire and the United Kingdom.
21st July 1932 - Imperial Economic Conference, Held to discuss the depression. Admitted failure of Gold Standard, also established a zone of limited tariffs within the British Empire, but with high tariffs with the rest of the world
Ireland
20th September 1914 - John Redmond of the Irish Parliamentary Party urges members of the Irish Volunteers to enlist to fight in the war. The majority (now known as the National Volunteers) join up, the minority (who retained 'Irish Volunteers'), don't.
2nd January 1920 - Recruitment in Britain for what would become known as the 'Black and Tans'.
25th February 1920 - Government of Ireland Bill introduced to the House of Commons
21st November 1920 - Assasinations of British agents in Ireland, 'Bloody Sunday' atrocity in answer to it.
10th December 1920 - Martial Law introduced in the counties of Cork, Kerry, Limerick and Tipperary.
22nd June 1922 - General Sir Henry Wilson, N. Irelands government advisor on security, assasinated by IRA gunmen in London
22nd August 1922 - Michael Collins killed
1930 - Military college at Curragh formed for regular cadets
1934 - The Volunteer Force, new reserve force, established
Hope this helps!