I'm 6ft 1" (Jonny) and I'm a lanky bugger but I could fit in it fine. We did have the large chassis one which supposedly is suitable for people up to 6ft 6". The standard chassis is suitable for people up to 6ft 2" but I sat in one and it was bloody tight!
Daniel, I’m just under 6’2” with 32” inside leg. I’ve got a S3 chassis with composite seats and have loads of leg room with my knees nowhere near the steering wheel. I’m guessing my body is where my height is held as I do sit quite high. We’ll below the screen and roll-bar, but with the side screens (doors) fitted, my vision to my right is sometimes obscured by the side screen surround. I am however so pleased I bought a S3 as I much prefer it’s looks / proportions. I did buy mine unseen from a dealer 500 miles from where I live without ever even sitting in a Caterham, it was quite an expensive gamble and I was somewhat terrified with the prospect of explaining to my wife I’d bought a car that I couldn’t drive or fit in. One thing I imagine you’ll need is a pair of racing boots. I’ve tried to drive mine with normal trainers and can almost push all the pedals at once when braking.