Ha ha! got it in just under wire!! a guess of course.
My first guess was the 1800, which was close, but wrong. and that threw me off. I don't know enough about pre-TR Triumphs without research, that I missed that the 1800 had the Flying Standard engine, where the 2000 got the Standard Vanguard engine. Otherwise the chassis were quite similar, from what I read.
Thanks for the brain excercise.