Hi, Rusty!
Mmm, I'm not convinced........ I know I have the answer "olive" correct - there is no doubt in my mind about that....
But I am half inclined to think that the compiler is in error and thinks that the Circle Line is 'green'......
I wish I could ask him/ her!
"Butty" is also a Northern word meaning "sandwich" - especially used in the north-west - and usually for a chip butty or a bacon butty.
It was in common usage when I was a child "up North"!
On reflection, I think my Scottish cousin used to say a chip "piece", when he meant a chip sandwich?
Throw my Chambers away, Rusty? when I am beginning to develop a reluctant affection for its idiosyncrasies/ funny little ways??
(Incidentally, it does have "birlinn" - although I had never heard of that word!)