The relevant section (§1) of the Computer Misuse Act 1990 states
(1) A person is guilty of an offence if— (a) he causes a computer to
perform any function with intent to secure access to any program or
data held in any computer, or to enable any such access to be secured;
(b) the access he intends to secure, or to enable to be secured, is
unauthorised; and (c) he knows at the time when he causes the
computer to perform the function that that is the case.
When a content-provider puts content "out in the open" in the described fashion, e.g. with a visible snippet of text, they are implicitly authorizing people to access the content (notice that web pages do not have to overtly announce "You are authorized to read this notice"). One approach to narrowing the access so granted is via a log-in scheme which send a portion of text then a "teaser", plus code which (upon authentication) loads the full page. Circumventing that method of access is a violation of the act.
Another method would be to include the entire content, by blurring, printing white on white, or some other form of display obfuscation, where display = scramble(plaintext). For example
<!DOCTYPE html><html> <head><title>Title</title><style>
#blur {font-size: 40px; color: transparent; text-shadow: 0 0 16px #000; }
</style></head><body><div id="blur">Pay money to see this </div></body></html>
When you enter your authorization code, the host computer performs a function (eliminates the scrambling in the code it sends to your computer, change 16 to 0). But you may be able to get the same result by inspecting the page source.
The crucial wording of the act says "causes a computer to perform any function...", but the host computer is not performing any function at all at this point, indeed the host may have melted down. The owner of the client computer can authorize his own computer to perform functions on data legally received from a host (you can read a web page, you can zoom in and out, all being locally-executed functions).
So it depends on the method of obfuscation used by the host. With that caveat, your analysis is correct.
