There aren't any aluminum MacBooks with this "L-shaped" return key of which you speak. Your eyes are probably playing tricks on you. Can you show us this video of which you speak?
The pictures on the Apple UK site must be of US models. Keyboards on British Macs have the inverted-L enter key, with the \ beside the ' key rather than beside the ] key.
They also have a shortened left shift key with the ` (grave) key beside it and a key with § (the "section" sign) and ± on it up next to the number 1 where I think the US model has the `. And they have a £ (pound sterling) sign instead of a number sign for shift-3.
This difference would be the one downside to picking up a shiny new Macbook next time I'm in the US...
Some European countries such as Sweden have the enter key in that format in order to make room for extra character keys. The MacBook depicted on most, if not all online, Apple Store localizations is the standard U.S. keyboard layout.