Horrid Henry, a British television show about a young boy named Henry, who is quite... horrid, he enjoys giving nicknames to his friends and enemies, he also has a brother, whom he addresses as “Perfect Peter”, who is the favourite child and becomes worse as the show progresses.
Tl:dr, Horrid Henry is fucking awesome.
Horrid Henry is a book series that later got a 5 season cartoon that aired in the mid 2000's on CITV in the UK. The series follows Henry, a boy who is deemed as being horrid to almost everyone.
The 4th season toned down Henry's antics due to complaints from adults about Henry being a bad influence on the youth. The 4th season is also ironically the best.
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.
British slang for a scientist or technical expert, esp . when the speaker is not certain of the expert’s specific field of study. Not necessarily derogatory, but typically used by persons without a technical background. In the US, the equivalent would be “egghead”, “squint”, or “geek.”
Origin of the word is unknown. Started sometime in World War 2. Given the typical evolution of British slang, could easily have started because what these experts did was confusing or “baffling” to the common person.