The battle of Albuera (1811) took place during the Peninsular War, when Anglo-Portuguese forces defeated the French.
The 57th (West Middlesex) Foot suffered very heavy casualties during the battle and later celebrated the anniversary as a regimental day.
The International Day against Homophobia, Transphobia and Biphobia is an official flag flying day only in Scotland, not in the rest of the UK.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
St Aldhelm (639–709) was Abbot of Malmesbury and Bishop of Sherborne.
Wiltshire Day takes place annually on 5 June.
It commemorates the first raising of the Wiltshire Flag at County Hall, Trowbridge (2007).
Sussex Day takes place annually on 16 June, the feast of St Richard of Chichester (1197–1253), the patron saint of Sussex.
Also known as Richard de Wych, the saint was bishop of Chichester.
Autistic Pride Day is an official flag flying day only in Scotland, not in the rest of the UK.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
The birthday of the Duke of Rothesay (Prince of Wales) is listed as a flag flying day by Scottish government guidance.
The Scottish Saltire is specified.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
The Birthday of the Prince of Wales is also listed as a flag flying day by UK government guidance.
The Union Flag is specified.
https://www.gov.uk/guidance/designated-days-for-union-flag-flying
Suffolk Day takes place annually on 21 June.
Former BBC radio presenter Mark Murphy created the event in 2016.
It has since become a staple in the Suffolk calendar, hosted by towns across the county.