The UK ISO numbers from base should be alpha colored, and you can move R1 PgDn and R1 End from base kit to numpad kit since they're for 1800 layout support.
Also your scroll lock legend in base says "Scroll" while the windowed version from the extension kit says "Scroll Lock." Not sure if this is on purpose or not, but it would make sense to me that the legend stays the same.
GLWIC!