Some things you might not know
The uk has only had decimal coinage for around 45 years. The idea of shillings crowns and sixpence might summon images of cars driving behind horse carriages and chimney sweeps at work, but its still within living memory for a large part if the population
London is one of the most important cities in the world. The city has so much opportunity that the best and brightest from all over the uk go to London o study and even work. The focus and investment put into London is a source of unhappiness for many, particularly those in the "second cities" like Manchester and Birmingham. If you want to make a lot of money at some point or go into an international business or firm, London is the easiest way to do that, and that acts as a brain drain for the rest of the country
Great Britain was created by the 1707 acts of union while the United Kingdom was created by the 1800 acts of union, parts of which have been repealed
Accents vary wildly; a 15 minute drive in either direction from my home would yield two noticeably different accents.
In music, our greatest classical composer was arguably a nationalised German, George Frideric Handel (originally Georg Friedrich Händel) whose most recognisable works are his Messiah choral masterpiece, his two collections of suites Water Music and Music for the Royal Fireworks and his famous coronation anthem, Zadok the Priest, more commonly known as "the Champions League theme." I'd love to link to these but I'm on mobile so its a bit fiddly. Other notable classical music composers are Benjamin Britten, Gustav Holst, William Byrd, Henry Purcell and Edward Elgar (famous for Pomp and Circumstance, the "British theme music" of many a 20th century film)
In more modern times, we have a plethora of rock, metal and new wave bands that achieved popularity internationally, most notably of course being The Beatles. The number of quality modern British artists is too numerous to even begin to list, but among my personal favourites are Pink Floyd, Judas Priest and the Stone Roses.
I shall add more to this later, have to get back to work for now. I'd also like to say this is definitely not textbook material, very subjective based on what I've experienced and read about. I'll try and talk about "banter" and our comedy/humour later.