Nowhere else in the world do they have egg and spoon races - well, not as far as I know. Car boot sales,however, are (were) a thing in many countries. Nowadays people get rid of their unwanted stuff via local websites.
The 'bumps' on birthdays and Maypole dancing are typically English, I think. The Scots have enough dances of their own. Not sure how far North the bumps were practised.
Just stopping to have a cup of tea. The observations in Asterix are not all overexaggerated stereotypes.
Tea ladies in offices. Probably a rarety these days, but surely worth their pay when I remember how many man-(woman)hours were spent making tea and coffee, washing cups, buying sugar and milk all the years I worked in offices where there was no tealady.
The Women's Institute. Most countries have an equivalent but they are nowhere near such an institution.
The Last Night of the Proms.