£80 is extortionate. I paid about £40 for mine from AliExpress, and they look the exact same. (I'd wager they are the same and one is rebranded, but that's me being cynical)
The AliExpress ones have a texture to them so look like the plastic on the sideskirts, the Osram are smooth like the OEM with a tinted and a normal version being offered. Volkswagen had also offered the Osram ones briefly as an OEM accessory from memory. As well as the Osrams are much brighter than both the originals and the chinese copies.
Not everyone will appreciate the subtle differences but I'd rather have a product from a well-known company who's business is producing lighting products as well as being able to provide ECE approval with a 5 year warranty.
Same principle as the golf really why pay more for a golf when a cupra is the same car for less?