Earlier quoted context omitted.
'kebob' isn't a well-known word in the UK. I believe it's a 'kebab' in the UK, They probably thought it was a trick question. Chucking in a word that sounds kind of like a real word, but spelled 'wrong'.
Quite a lot of restaurants in the UK also spell it as kebop, so I'd have thought many people would also be able to guess kebob.
I guess you've seen it somewhere so your observation is equally as valid as mine, but I've lived (UK) in the North West, Midlands, and South West, and have worked in London, and I've never seen the word kebop anywhere ever.