Bletchley Park’s use of adtech means you can’t opt out of non-essential cookies and still access the website
I found this ironically sad.
Visit Bletchley Park’s website and one is presented with a cookie banner. If you’re like me you will deselect all but essential cookies – so no “preferences”, “statistics” or “marketing”

Regulation 6 of the Privacy and Electronic Marketing (EC Directive) Regulations 2003 (PECR) is behind this.
As much as one might find cookie banners annoying, they are a result of cookies being inherently intrusive. They are code placed on one’s terminal equipment; sometimes they are essential for a website’s functioning (in which case they can be placed without consent) and sometimes they are merely useful (but not essential) for the user or the operator – perhaps to get analytics, or remember preferences, or deliver targeted advertising (in which case user consent is required).
The problem with the Bletchley site is that if one refuses “non-essential” cookies (I tried on Edge, Chrome and Safari mobile), they turn out to be rather essential, because what one is left is this

I only spent a few minutes trying to work out if it was some clever puzzle you had to crack to gain access before I realised it was just poor configuration.
So, in fact, the non-essential cookies are actually essential.
I’m sure someone with some expertise in code can sort it out. It can’t be beyond the wit of those running Bletchley Park to configure a website so that it functions properly without interfering with visitors’ computers.
The views in this post (and indeed most posts on this blog) are my personal ones, and do not represent the views of any organisation I am involved with.